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Messages - xiangjun

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1276
Bug reports / Report 3DNA bugs
« on: February 24, 2012, 02:15:31 pm »
Hi all,

Over the years, it is the constructive interactions with the user community that has driven 3DNA to its current prominent status. Please do not hesitate to report bugs -- the more, the merrier. I strive to fix any identified bugs as soon as possible.

The following is a list of known bugs in the current release of 3DNA v2.0 that have all been fixed in v2.1:
  • The fiber utility fails to local model directory. This is a very subtle bug that has existed from the very beginning, but is known to show up only in Fedora 14 64-bit Linux machine. Fixed in v2.1beta as of 2012-02-23. Thanks to esguerra!
  • Parameter std_curved not working. This bug was first reported by slaw in the thread "Global Helical Axis Information Missing", and was recently rediscovered by esguerra. For the current v2.0 users who need this feature, the workaround is to modify file 'misc_3dna.par' as follows:
    <std_curved >0.6</std_curved >   # add a space in the end of the tag!

1277
Hurrying for a meeting this morning, I did not notice the new set of 4 structures you attached when I posted my previous reply. Now things are becoming quite interesting. My arguments with regard to the first set of four structures you provided (Srini_PP.pdb, Srini_MM.pdb, Srini_PM.pdb and Srini_MP.pdb) still hold, i.e., PP=MM, and PM≈MP. There is no such things as "four distinctly different structures" there.

The new set of four structures (Srini_pp1.pdb, Srini_mm1.pdb, Srini_pm1.pdb, Srini_mp1.pdb), hereafter referred as PP1, MM1, PM1 and MP1, are completely different from the first set. 3DNA has no problem in identifying the four distinct forms, based on exactly the same algorithm as described in the 1997 JMB SCHNAaP paper. For example, for MM1, the output from 3DNA is as below:

Code: [Select]
****************************************************************************
Structure classification:

This is a right-handed unknown R-form structure
****************************************************************************

More specifically, Figure 7 of the SCHNAaP paper answers this question:


Quote
Figure 7. A representation of four possible arrangements for antiparallel nucleic acid duplexes. Left-handed W and Z-DNA are shown on the left (the characteristic zig-zag backbone pattern is not represented for simplicity). Right-handed A/B and hypothetical R-DNA are shown on the right. The Twist free ladder forms are shown in the middle column. In the top row, the minor groove faces the viewer, while in the bottom row, the major groove faces the viewer. The SCHNAaP coordinate system is also shown. These structures were generated using SCHNArP (see accompanying paper) with Twist= ±36° (0° for the ladder forms), Rise=3.34 Å, and all other step parameters are set to zero. Color scheme: the minor groove side, dark green; the major groove side, light green; and the backbone, red.

In connection with the new set of 4 structures, they correspond to the four forms classified in 3DNA (SCHNAaP) as below:
  • PM1: W-form, left-handed
  • MP1: Z-form, left-handed
  • PP1: A/B-form, right-handed
  • MM1: R-form, right-handed
Also as in SCHNAaP, right-handed structures (PP1/MM1) have positive Twist, and left-handed structures (PM1/MP1) have negative Twist. Moreover, they all have positive Rise.

I am really pleased to see the model structures representing the 4 possible distinct forms of double helices. I will consider to include them in future releases of the 3DNA distribution.

Xiang-Jun

1278
Bug reports / Re: Problems using fiber in version 2.1 -- 2012
« on: February 23, 2012, 03:42:32 pm »
Hi Mauricio,

Quote
Problem fixed with fiber-2

Thanks for your feedback -- I am glad to hear that the problem has been solved. You are so great :) in helping me identify and fix this very subtle bug that can be traced back to v1.5! The tricky part is that it normally does not show up -- not on CentOS 5, Scientific Linux 6, Debian 5, Debian 6, Ubuntu 10.10 and OpenSuSE 11.3. Even if I compile 3DNA directly on Fedora 14 64bit, everything runs smoothly.

This is an excellent example to show that a software program can never be claimed bug-free, and why user's feedback is always appreciated in my support of 3DNA. Please do not be shy to report back any issue you experience that can potentially help made 3DNA better.

As a side note with the fiber application, it's an old dog with new tricks in 3DAN v2.1. For example, to generate a single stranded RNA with sequence "aaauuuggc", it can now be conveniently done as below:
Code: [Select]
fiber -s -r -seq="aaauuuggc" rna_model.pdb
Thanks again for your help in fixing this bug!

Xiang-Jun

1279
In the .par file, the so-called "R matrix" is actually the amino-acid-side-chain expressed when the corresponding base-pair reference frame is at [1 0 0; 0 1 0; 0 0 1] after coordinate transformation.

To verify, simply find the corresponding .pdb for a .par entry, and extract the xyz coordinates of both Cα and Cβ atoms. Then the unit vector of Cα→Cβ corresponds, approximately, to the x-axis (the first row of the "R-matrix"). Please post back an example.

Xiang-Jun

1280
Then we may have different understanding as to what it means to be of the same structure: to me, since PP and MM have an RMSD of 0, they are IDENTICAL. Naturally, 3DNA should output the SAME parameters, as it does. As mentioned in my previous post, the case of PM vs MP follows the same argument.

Ask Sriri to show here in details most possible, how and why PP and MM are different.

Xiang-Jun

1281
Hi Wilma,

Thanks for bringing up this "issue". As always, the four concrete PDB files helped clarify everything. In short, 3DNA is behaving properly: because PP and MM are IDENTICAL (RMSD=0 Å), so are PM and MP (RMSD=0.0174364 Å). There are only two structures; the PP/MM pair is right-handed with Rise=+3.4Å, and Twist=+36°, whilst the PM/MP pair is left-handed Rise=+3.4Å, and Twist=–36°.

Now let's get into details to see why PP=MM, and PM=MP.
  • The PP vs MM case is clear-cut:
    head Srini_PP.pdb Srini_MM.pdb
    ==> Srini_PP.pdb <==
    ATOM      1  P     A A   1      -0.299   9.399  -1.529
    ATOM      2  O1P   A A   1      -0.377  10.734  -2.162
    ATOM      3  O2P   A A   1       0.714   9.245  -0.460
    ATOM      4  O5'   A A   1      -1.738   8.985  -0.968
    ATOM      5  C5'   A A   1      -2.674   8.343  -1.855
    ATOM      6  C4'   A A   1      -3.346   7.182  -1.148
    ATOM      7  O4'   A A   1      -2.596   5.941  -1.284
    ATOM      8  C3'   A A   1      -3.530   7.338   0.361
    ATOM      9  O3'   A A   1      -4.771   6.752   0.737

    ==> Srini_MM.pdb <==
    ATOM      1  P     A A   1       0.299   9.399   1.529
    ATOM      2  O1P   A A   1       0.377  10.734   2.162
    ATOM      3  O2P   A A   1      -0.714   9.245   0.460
    ATOM      4  O5'   A A   1       1.738   8.985   0.968
    ATOM      5  C5'   A A   1       2.674   8.343   1.855
    ATOM      6  C4'   A A   1       3.346   7.182   1.148
    ATOM      7  O4'   A A   1       2.596   5.941   1.284
    ATOM      8  C3'   A A   1       3.530   7.338  -0.361
    ATOM      9  O3'   A A   1       4.771   6.752  -0.737
    The simple head Unix command shows clearly PP and MM are related by a rotation about y-axis by 180°. Thus, the two structures have identical y-coordinates, but opposite x- and z-coordinates. Naturally, the RMSD between them is perfectly 0.
  • The case for PM vs MP is similar, as shown below.
    head Srini_PM.pdb Srini_MP.pdb
    ==> Srini_PM.pdb <==
    ATOM      2  O5*   A A   1       1.736   9.011  -0.504   1.0   0.0           O
    ATOM      3  C5*   A A   1       2.715   8.816   0.515   1.0   0.0           C
    ATOM      6  C4*   A A   1       3.299   7.393   0.557   1.0   0.0           C
    ATOM      8  O4*   A A   1       2.287   6.447   0.872   1.0   0.0           O
    ATOM      9  C1*   A A   1       2.480   5.346   0.001   1.0   0.0           C
    ATOM     11  N9    A A   1       1.290   4.498   0.000   1.0   0.0           N
    ATOM     12  C8    A A   1      -0.023   4.897   0.000   1.0   0.0           C
    ATOM     14  N7    A A   1      -0.878   3.903   0.000   1.0   0.0           N
    ATOM     15  C5    A A   1      -0.071   2.772   0.000   1.0   0.0           C

    ==> Srini_MP.pdb <==
    ATOM      2  O5*   A A   1      -1.747   9.015   0.517   1.0   0.0           O
    ATOM      3  C5*   A A   1      -2.723   8.818  -0.506   1.0   0.0           C
    ATOM      6  C4*   A A   1      -3.301   7.393  -0.552   1.0   0.0           C
    ATOM      8  O4*   A A   1      -2.286   6.450  -0.867   1.0   0.0           O
    ATOM      9  C1*   A A   1      -2.480   5.346  -0.001   1.0   0.0           C
    ATOM     11  N9    A A   1      -1.290   4.498   0.000   1.0   0.0           N
    ATOM     12  C8    A A   1       0.023   4.897   0.000   1.0   0.0           C
    ATOM     14  N7    A A   1       0.878   3.903   0.000   1.0   0.0           N
    ATOM     15  C5    A A   1       0.071   2.772   0.000   1.0   0.0           C

    The two structures have an RMSD of only 0.0174364 Å, which can be taken as zero in practical sense. For verification purpose, please download the superimposed PDB coordinates of PM onto MP (Srini-PM2MP.pdb), and its combination with the original MP in a MODEL/ENDMDL delineated PDB file (Srini-MP-PM-aligned.pdb).

    You can use Jmol or PyMOL to easily view the aligned structure file Srini-MP-PM-aligned.pdb to see for yourself how they overlap. Given below is the "nmr_ensemble" generated image based on Srini-MP-PM-aligned.pdb. Obviously, the two structures align virtually perfectly, in agreement with an RMSD of less than 0.02 Å.


I do not quite understand how Srini and you come to the conclusion that 3DNA is in error here. Unless I am missing something obvious, it is hard for me to imagine that simply rotate a DNA structure by 180 degrees about the y-axis should reverse its Rise and Twist. Maybe Srini can shed more light on his thought?

Xiang-Jun

1282
Bug reports / Re: Problems using fiber in version 2.1 -- 2012
« on: February 22, 2012, 08:18:22 pm »
Hi Mauricio,

You may have helped trace a subtle bug that only shows up in specific OS (here, fedora 14 64bit). Download the following two modified versions of fiber, named fiber-1 and fiber-2. Copy them into $X3DNA/bin, and then run the following, and report back verbatim what you see from screen (as I did in my first reply).

Code: [Select]
fiber-1 -a -seq="aattgg" fa-1.pdb
fiber-2 -a -seq="aattgg" fa-2.pdb

If I have fixed the bug, then the second version (fiber-2) should run successfully, and fiber-1 should provide further information about the source of the bug.

Please let me know how it goes.

Xiang-Jun

1283
Bug reports / Re: Problems using fiber in version 2.1 -- 2012
« on: February 22, 2012, 10:29:55 am »
Hi Mauricio,

Thanks for providing further information. I'll dig the issue further to see if I can reproduce the problem in machines I have access to, and then get back to you ...

Best regards,

Xiang-Jun

1284
Bug reports / Re: Problems using fiber in version 2.1 -- 2012
« on: February 22, 2012, 08:12:27 am »
Quote
open_file <str01/A.rpt> failed: No such file or directory
Weird -- that certainly should not happen! What do the following output?

Code: [Select]
echo $X3DNA
ls $X3DNA/fiber

I've just tried on my machine. As the screen output shows below, the program is working as expected:
Code: [Select]
tmp [510] fiber -a ADNA.pdb
Fiber data in directory: /Users/xiangjun/X3DNA/x3dna-v2.1beta/fiber/

 ...... /Users/xiangjun/X3DNA/x3dna-v2.1beta/config/ ......
 ...... reading file: misc_3dna.par ......
Structure #1; Twist: 32.7 (degrees); Rise: 2.548 (Angstrom)

Input your base sequence with only ACGT:
1. From a data file (complete sequence)
2. From keyboard (enter only the repeating sequence)
Your choice (1 or 2, Dft: 2):

Repeating unit (Dft: A):
Repeating unit: A
Number of repeats (Dft: 10):

Xiang-Jun

1285
The six parameters are just as "shear/stretch/stagger/buckle/propeller/opening" for base-pair parameters, and "shift/slide/rise/tilt/roll/twist" for the dinucleotide steps -- they quantify the spatial relationship rigorously between the side-chain reference frame and the base-pair reference frame. The technical details part (section #5) in the 3DNA manual contains a worked example on how to calculate step parameters. If you really want to get to the bottom of the matter, it's well worthwhile to repeat the example and try to understand every detail.

Quote
In the Siggers (2005) paper, they only used delta a and delta theta  describing the rotation angle.
Mathematically, to rigorously quantify the rotational relationship between two rigid bodies, three angular parameters are required. The Siggers method is a just an approximation, which may be sufficient for its purpose. To understand how the Siggers method works, you may need to dig into the source code -- simply reading the paper is not enough for the algorithmic details.

In light of this topic, you may want to pay more attention to the following quote:

Quote from: Siggers 2005 JMB paper
The approach used here is similar to that described by Pabo & Nekludova, but with two important differences. (1) Three geometric parameters [instead of two] are used in the comparison of residue-base-pairs, a feature that we found to increase the sensitivity of our analysis. ...

Xiang-Jun

1286
General discussions (Q&As) / Re: building a custom dna triplex
« on: February 16, 2012, 04:00:59 pm »
Hi George,

Thanks for posting at the new 3DNA forum!

One way to build a standard DNA triplex with a mixture of TAT and CGC(+) triples would be first to build a Poly (U) : poly (A) : poly(U) triplex, using fiber model #32, or another one as you see fit. Run fiber -l for a list of possible fiber models available from 3DNA, and read the 3DNA 2003 NAR paper for details.

Next, you can use mutate_bases to mutate A/U to the bases you need. See the documentation for details -- currently mutate_bases is the only program I have documented.

Third, you need to download 3DNA v2.1beta which has mutate_bases incorporated as an integral part of the new distribution.

Note that 3DNA v2.1 is only in beta test version. If you notice any issues, please report back.

Best regards,

Xiang-Jun



1287
Bug reports / Re: file format v2.1 and Kaisen
« on: February 16, 2012, 08:34:33 am »
Quote
But please, let me first know if you changed any of the output file format. It is crucial for me to know if, where and which changes have been made.
The file format has not changed in v2.1. That's one of the fundamental considerations I've in mind. Of course, if you notice anything otherwise, I will fix it.

Quote
Also, have you an updated and detailed manual somewhere ? This is one of the very important and often missed feature of such important packages.
Documentation is the next priority now that the v2.1beta is ready for outside testing. You are welcome to point out any areas that I should make clearer and/or document more deeply.

Quote
(your link to "kaisen" searches for kaisen" and thus does not find the correct page)
((this is my tiny contribution to this bug report section))
Fixed. Just remember that no contribution is tiny! The forum is migrated from the original phpBB3, and many links and content should be corrected. I make them available now simply because the forum is functioning, and I would like to hear more feedback from users and earlier. I welcome each and every contribution from the user community.

Xiang-Jun


1288
General discussions (Q&As) / mutate_bases
« on: February 11, 2012, 06:47:28 pm »
Note added on 2020-05-12: mutate_bases is now obsoleted by DSSR 2.0.

See also:

The utility program mutate_bases can be used to mutate bases in nucleic-acid-containing structures (DNA, RNA, and their complexes with ligands and proteins). It has two key and unique features: (1) the sugar-phosphate backbone conformation is untouched; (2) the base reference frame (position and orientation) is conserved, i.e., the mutated structure shares the same base-pair/step parameters as those of the native structure.

The mutate_bases program was created in response to repeated requests from 3DNA users over the years. Written as a standalone ANSI C program, it is on a par with other major 3DNA components (e.g., find_pair, analyze, rebuild and fiber). The program was first released as a supplement to 3DNA v2.0, and then became an essential part of the v2.1 release.

Overall, mutate_bases has been designed to solve the in silico base mutation problem in a practical sense: robust and efficient, getting its job done and then out of the way. The program can have many possible applications: in addition to perform base-pair mutations in DNA-protein complexes, it should also prove handy in RNA modeling and in providing initial structures for QM/MM/MD energy calculations, and in DNA/RNA modeling studies.

The standard command line help (mutate_bases -h) is as below:
NAME
        mutate_bases -- mutate bases, with backbone conformation unchanged
SYNOPSIS
        mutate_bases [OPTIONS] mutinfo pdbfile outfile
DESCRIPTION
        perform in silico base mutations of 3-dimensional nucleic acid
        structures, with two key and unique features: (1) the sugar-
        phosphate backbone conformation is untouched; (2) the base
        reference frame (position and orientation) is reserved, i.e.,
        the mutated structure shares the same base-pair/step
        parameters as the original one.
        -e    enumeration of all bases in the structure
        -l    name of file, containing list of mutations
        'mutinfo' can contain upto 5 fields for each mutation
                  [name=residue_name] [icode=insertion_code]
                  chain=chain_id seqnum=residue_number
                  mutation=residue_name
            The five fields per mutation can be in any order or CaSe.
            Each field can be abbreviated to its first character.
            Multiple mutations specified per line are separated by ';'.
            Fields in [] (i.e., name and icode) are optional.
            Mutation info should be QUOTED to be taken as one entry.
INPUT
        Nucleic-acid-containing structure file in PDB format
EXAMPLES
            # mutate G2 in chain A of B-DNA 355d to Adenine
        mutate_bases "c=a s=2 m=DA" 355d.pdb 355d_G2A.pdb
            # mutate the second base-pair G-C to A-T in 355d
        mutate_bases "c=a s=2 m=DA; c=B s=23 m=DT" 355d.pdb 355d_GC2AT.pdb
            # the above also generates file 'mutations.dat'
            # and the following command gives the same results
        mutate_bases -l mutations.dat 355d.pdb 355d_GC2AT_v2.pdb
            # mutate C74 in chain A of tRNA 1evv to U       
        mutate_bases "c=A s=74 m=U" 1evv.pdb 1evv_C74U.pdb
            # list all bases to be tailored for mutation
        mutate_bases -e 355d.pdb stdout
OUTPUT
        mutated structure in PDB format, sharing the same backbone
        conformation and base pair parameters as the original one.
SEE ALSO
        analyze, find_pair, rebuild
AUTHOR
        3DNA v2.1 (c) 2012 Dr. Xiang-Jun Lu (http://x3dna.org)


Now let's take advantage of the web to illustrate the key features of mutate_bases using a set of worked examples. The scripts and corresponding data files & images are attached, so you can repeat the procedures in order to have a better understanding of how the program works.

In our GpU dinucleotide platform paper, we reported a previously unnoticed intra-dinucleotide sugar-phosphate H-bond that is unique to the GpU platform. This O2′(G)···O2P(U) H-bond readily rationalizes the over 60% occurrence of GpU over other platforms (e.g., ApA and UpC). Moreover, this H-bond has recently been validated by state-of-the-art quantum-chemical techniques.

In this section, we will use mutate_bases to answer the questions of (1) why GpU, not GpT? i.e., why the GpU platform is RNA-specific? (2) why no UpG platforms observed? i.e., why the GpU platform is directional? The GpU platform (1msy_gu.pdb) is derived from PDB entry 1msy. The figure below shows the identity of the two nucleotides (G2655 and U2656 on chain A) and names of the base atoms.

"GpU platform" title="GpU platform"

  • Why no GpT platform?
    mutate_bases "c=a s=2656 m=t" 1msy_gu.pdb 1msy_gt.pdb
    With the above command, we mutate U (which is residue #2656 on chain A) to T (see figure below). Clearly, the methyl group of T protrudes into the pocket, causing steric clash. Thus GpT is incompatible with the platform conformation.

    "GpT platform?" title="GpT platform?"

  • Why no UpG platform?
    mutate_bases "c=a s=2655 m=u; c=a s=2656 m=g" 1msy_gu.pdb 1msy_ug.pdb
    Using the above command, we mutate G (which is residue #2655 on chain A) to U, and U to G simultaneously. That's what the plural 's' in mutate_bases stands for. From the figure below, one can see clearly that no intra-base H-bond is now possible, consistent with the fact that no UpG platform has been observed.

    "no UpG platform!" title="no UpG platform!"

    Note that the above command also generates a file named 'mutations.dat', which has the following content:
    c=a s=2655 m=u
    c=a s=2656 m=g
    You can then use the -l option of mutate_bases as such:
    mutate_bases -l mutations.dat 1msy_gu.pdb 1msy_ug2.pdb.
    The two mutated PDB files, 1msy_ug.pdb and 1msy_ug2.pdb, are identical.
You can run find_pair and analyze to the raw and mutated PDB files and verify that they indeed have the same base-pair parameters and backbone conformation.

To summarize, here is the command-script:
Code: [Select]
mutate_bases "c=a s=2656 m=t" 1msy_gu.pdb 1msy_gt.pdb
mutate_bases "c=a s=2655 m=u; c=a s=2656 m=g" 1msy_gu.pdb 1msy_ug.pdb
mutate_bases -l mutations.dat 1msy_gu.pdb 1msy_ug2.pdb

The PDB files referred:

Note all the images used in this post were generated using Jmol. As much I like RasMol (v2.6.4), I am now gradually switching to Jmol and PyMOL.


Note added on Monday, July 17, 2017:

Single quotes in mutate_bases command-line option have been replaced by double quotes so that the program also works in native Windows. See follow-up messages below.

1289
General discussions (Q&As) / find_pair
« on: February 11, 2012, 06:44:09 pm »
find_pair now contains -c+ option to generate input for Curves+.

1290
Feature requests / Re: Align multi-model (NMR) structures
« on: February 01, 2012, 12:41:35 pm »
Hi Andrew,

That's certainly possible. I will get this functionality added shortly so you can try it. I am consolidating the ensemble-related scripts into one, named 'x3dna_ensemble' with sub-commands such as 'analyze', 'extract', 'reorient', and more. So the new way to run the command would be "x3dna_ensemble reorient" plus options.

Xiang-Jun


Added on 2012-Feb-15: the current 3DNA v2.1beta can be downloaded from: http://x3dna.org/download/

1291
FAQs / How do I cite 3DNA?
« on: January 25, 2012, 06:11:55 pm »
Please use at least one of the following literature references:
The current citation list to 3DNA can be found in Google scholar.

1292
General discussions (Q&As) / How to install 3DNA on Linux and Windows?
« on: January 24, 2012, 03:36:30 pm »
3DNA is a command-line driven software tool, developed and tested in Linux/Mac OS X systems. It can also be easily installed on other Unix variants, including Cygwin and MinGW/MSYS in Windows. The following instructions are targeted on two typical scenarios: one for Linux, and the other for MinGW/MSYS-based Windows.

As of 3DNA v2.1, Ruby has replaced Perl as the scripting language. Therefore, you must also have Ruby installed on your system. 3DNA has no dependence on any third-party gem, and has been tested on Ruby 1.8.x and 1.9.x series. Even though Ruby may not be installed by default on your system, the software is widely available on all common OSes, and should be straightforward to install.

As of 3DNA v2.3-2016sept06, the C source code is available (under the folder $X3DNA/src).

On Linux (including Mac OS X, or Cygwin on Windows)
Assuming the downloaded tarball file is named x3dna-v2.3-linux-64bit.tar.gz. At your current working directory (presumably your home directory), do the following:
  • tar pzxvf x3dna-v2.3-linux-64bit.tar.gz
    Here the options pzxvf require some explanation:
    • p to preserve permissions of the various directories and files. This option may not be required for a personal setting.
    • z filter the archive through gzip. With this option, we can work directly from .tar.gz file without first using gunzip.
    • x to extract files from an archive.
    • v to verbosely list files processed.
    • f to use archive file, i.e., the 3DNA tarball file x3dna-v2.3-linux-64bit.tar.gz.
    After running the above command, you will get a directory named x3dna-v2.3 which contains the 3DNA v2.3 distribution.
  • cd x3dna-v2.3/bin
    enter into the bin directory of the 3DNA v2.3 distribution.
  • ./x3dna_setup
    run the 3DNA setup Ruby script, and you will see an output similar to the following:
    To install X3DNA, do as follows:
      (0) download 3DNA binary distribution for your system from URL
              http://x3dna.org
      (1) tar pzxvf x3dna-v2.3-linux-64bit.tar.gz
      (2) cd x3dna-v2.3/bin
      (3) ./x3dna_setup
            To run X3DNA, you need to set up the followings:
              o the environment variable X3DNA
              o add $X3DNA/bin to your command line search path
              for your 'bash' shell, please add the following into ~/.bashrc:
              --------------------------------------------------------------
                export X3DNA='/home/xiangjun/x3dna-v2.3'
                export PATH='/home/xiangjun/x3dna-v2.3/bin':$PATH
              --------------------------------------------------------------
              and then run: source ~/.bashrc
      (4) type find_pair -h
            for command line help -- this applies to all 3DNA binaries
            Visit 3DNA homepage at URL http://x3dna.org/ for more info.
    Here the key parts are colored red, i.e., set the environment variable X3DNA and add $X3DNA/bin to your command search path.

    The above example refers to the most commonly used 'bash' shell. For the 'sh' shell, the 'x3dna_setup' output would be:
              for your 'sh' shell, add the following into ~/.profile:
              --------------------------------------------------------------
                  export X3DNA='/home/xiangjun/x3dna-v2.3'
                  export PATH='/home/xiangjun/x3dna-v2.3/bin':$PATH
              --------------------------------------------------------------
              and then run: source ~/.profile
    You may need to use the dot command: . ~/.profile. For the 'tcsh' (or 'csh') shell, the 'x3dna_setup' output would be:
              for your 'tcsh' shell, add the following into ~/.cshrc:
              --------------------------------------------------------------
                setenv X3DNA '/home/xiangjun/x3dna-v2.3'
                setenv PATH '/home/xiangjun/x3dna-v2.3/bin':$PATH
              --------------------------------------------------------------
              and then run: source ~/.cshrc
    If your shell is none of the four recognized ones -- bash, sh, tcsh, or csh -- or cannot be detected, the script still outputs sensible settings about the installation.
  • find_pair -h
    or ./find_pair -h if you've strictly followed the steps above, and your current working directly is not in the command search path. Now you should see a screenful of command-line help. Congratulations -- You now have 3DNA properly installed! If otherwise, please post here with details, and we will try to help you out.

On native Windows (added on July 14, 2017)
See FAQ entry: "How to set up 3DNA on Windows"?

On MinGW/MSYS--based Windows
First, you need to install MSYS2 and Ruby on Windows. Depending on your experience, you may need to seek help from local experts. The following is a general guideline to get you started. Overall, it should be quite straightforward.

  • Use MSYS2 installer to install MSYS2, either 32-bit or 64-bit is fine. I've found MSYS2 to be simpler to install than the original MinGW/MSYS system.
  • Then install the latest version of Ruby with "Ruby Installer". In the "Installation Destination and Optional Tasks" section, be sure to select "Add Ruby executables to your path", and "Associate .rb and .rbw files with this Ruby installation".

After installing MinGW/MSYS, double-click the "M" (msys) icon on the desktop to start the MSYS shell.. See the thread "How to install 3DNA on MinGW/MSYS".

Then follow the instructions above on installing 3DNA on Linux.

Compile 3DNA from the source code
  • Follow step #1 for Linux (above) to extract the 3DNA tarball to its own folder (x3dna-v2.3)
  • cd x3dna-v2.3/src
    Then type make
    The gcc compiler is assumed in the Makefile. If you have a non-gcc compiler, you should modify the following two lines as appropriate:
    CFLAGS      = -ansi -pedantic -W -Wall -Wextra -Wunused -Wshadow  -O3
    CC      = gcc
    Since 3DNA is implemented in strict ANSI C, it should compile without any changes with any modern C compiler.
    Then follow steps 2-4 above for Linux to set the X3DNA and PATH environment variables.

1293
Feature requests / Re: Align multi-model (NMR) structures
« on: January 24, 2012, 08:23:00 am »
Hi Andrew,

I've finally wrote the Ruby script named 'ensemble_reorient' to perform multiple-model ensemble alignment. In it took longer than I originally planned, and for good reasons  :). In the process, I've consolidated and refined the two Ruby scripts ('x3dna_md.rb' and  'extract_par.rb') for the analysis of MODEL/ENDMDL delineated molecular dynamics trajectories and NMR ensembles. For consistency, I've renamed them 'ensemble_analyze' and 'ensemble_extract'.

The ensemble_* scripts, together with added new C programs 'mutate_bases' and 'find_platform' will be released in 3DNA v2.1 in the near future. For backward compatibility, all v2.0 Perl scripts are going to be retained. From v2.2 and onwards, I am planning to eliminate all Perl scripts and use solely Ruby as the script language. 

Check email to see download info for the v2.1 beta version for testing. There are still lots of rough edges, but with the groundwork laid so far, I should be able to respond quickly to any identified issues.

The help message for 'ensemble_reorient' is as follows:

------------------------------------------------------------------------
Usage:
        ensemble_reorient options
Examples:
        ensemble_reorient --frame-opt='-m -6' -b bpfile.dat -e 2kei.pdb
             # reorient each model using the reference frame of base-pair #6
             #     with minor groove facing the viewer (-m)
             # note the use the double dash (--) style with equal sign, and
             #     the options to be transfered to frame_mol must be quoted
             # generate 'model_list.dat', and 'ensemble_example_trx.pdb'
        ensemble_reorient -f '\-m -6' -b bpfile.dat -m model_list.dat -o reoriented.pdb
             # Same transformation as above, but using an explicit list of
             #     models, and the transformed ensemble in 'reoriented.pdb'
             # diff ensemble_example_trx.pdb reoriented.pdb
        ensemble_reorient -f '\-8,9' -b bpfile.dat -e 2kei.pdb
             # reorient each model using the middle reference frame between
             #     base-pairs #8 & #9. Again, note the quote and back slash
Options:
------------------------------------------------------------------------
     --bpfile, -b <s>:   File containing base-pairing info (as generated from find_pair,
                         and EDITED as appropriate) 
    --outfile, -o <s>:   Output parameters file name (default: ensemble_example_trx.pdb)
  --frame-opt, -f <s>:   Options to transfer to frame_mol (quoted)
   --ensemble, -e <s>:   Model ensemble delineated with MODEL/ENDMDL
     --models, -m <s>:   File with explicit listing of model numbers
           --help, -h:   Show this message

Please check and report back any issues you experience.

Xiang-Jun

1294
There are currently two consecutive standards on the nomenclature and definition of nucleic acid structural parameters, the initial 1989 Cambridge Convention, and the 1999/2001 Tsukuba Report (standard base-reference frame).

The 1989 Cambridge Convention

The 1989 EMBO Workshop (held at Cambridge, England) provided the first systemic "definitions and nomenclature of nucleic acid structure parameters" [Dickerson et al. (1989), Nucleic Acids Res., 17(5), 1797-803]. Thereafter, several analysis programs were updated or created (most notably Curves from Richard Lavery and NewHelix/FreeHelix from Richard Dickerson), following the loosely defined convention. Even though the parameters are now named the same, the different programs can provide conflicting numerical values, especially for strongly distorted structures. See, for example, Werner et al. (1996) "Intercalation, DNA kinking, and the control of transcription" [Science, 271(5250), 778-84].


The 1999 Tsukuba Workshop

Our efforts in "resolving the discrepancies among nucleic acid conformational analyses" uncovered the source of the disparate descriptions from commonly used software programs:

Quote
Growing interest in understanding the relationship between the global folding of nucleic acids and the sequence-dependent structure of individual base-pair steps has stimulated the development of new mathematical methods to define the geometry of the constituent base-pairs. Several approaches, designed to meet guidelines set by the nucleic acid community, permit rigorous comparative analyses of different three-dimensional structures, as well as allow for reconstruction of chain molecules at the base-pair level. The different computer programs, however, yield inconsistent descriptions of chain conformation. Here we report our own implementation of seven algorithms used to determine base-pair and dimer step parameters. Aside from reproducing the results of individual programs, we uncover the reasons why the different algorithms come to conflicting structural interpretations. The choice of mathematics has only a limited effect on the computed parameters, even in highly deformed duplexes. The results are much more sensitive to the choice of reference frame. The disparate schemes yield very similar conformational descriptions if the calculations are based on a common reference frame. The current positioning of reference frames at the inner and outer edges of complementary bases exaggerates the rise at distorted dimer steps, and points to the need for a carefully defined conformational standard.

This work laid the foundation for the standardization of the base-pair parameters in the 1999 Tsukuba Workshop on Nucleic Acid Structure and Interactions. Following public review and discussion, and final approval by the IUBMB Nomenclature Committee, the standard base-reference frame paper came out in 2001 [PDF from the Nucleic Acids Database (NDB)]. From the initiation to its completion, the standardization was made possible by the NDB project, led by Helen Berman.

While not a participant of the 1999 Tsukuba Workshop, I was nevertheless heavily involved in the preparation of the final report. In the following posts at this section, I am planning to provide full data files and scripts so the Figures and Tables can be re-generated. In addition to serving as learning materials for new comers to the field of nucleic acid structures, the details should also be of interest to seasoned practitioners to watch for the caveats. From my own perspective, the work is directly relevant to the automatic identification and classification of non-canonical base pairs in RNA structures, among other possible applications already implemented in or to be added to 3DNA.

To the best of my knowledge, currently only 3DNA and Curves+ conform to the standard base-reference frame; as a result, the structural parameters (for Watson-Crick base-pair duplexes) calculated by the two programs are very similar.

Related PDF Documents

1295
Users' contributions / Re: deformation energy calculation program
« on: January 07, 2012, 11:49:30 pm »
Quote
Please note that these two tests fail with the deformation energy program currently distributed on the 3DNA website at:

http://rutchem.rutgers.edu/~xiangjun/3DNA/users.html

The above note refers to the C++ program written by Marc Parisien (University of Montreal, Canada) for calculating deformation energies at the base-pair or dinucleotide step level. Since the referred to URL is now dysfunctional, I have consolidated all the related information here.

-- Xiang-Jun


Email message from Marc Parisien on the C++ program ('EnergyPDNA.C' and the associated header file 'EnergyParams.h' are attached below)

From parisien@iro.umontreal.ca
Date: Mon, 10 May 2004 11:28:18 -0400 (EDT)
From: Marc Parisien <parisien@iro.umontreal.ca>
Cc: xiangjun@rutchem.rutgers.edu, songliu@buffalo.edu
Subject: DNA deformation energy!


Hi All!

   I have received the mean values from Dr. Lankas;

        Lankas F, Sponer J, Langowski J, Cheatham TE 3rd.
          DNA deformability at the base pair level.
          J Am Chem Soc. 2004 Apr 7;126(13):4124-5.

   We now have the base-pair level deformation energies!!
   I have updated the program; see attached files :-)


   I have decoupled the energy calcs since there is the possibility
of coupled interactions between base-pairs and base-steps parameters...
(like Propeller-Rise, etc)   another article maybe for that ;-)
It would generate a huge matrix though: 12 x 12  (6 params for bases + 6
params for steps = 12 total params).

   I have also change the energy calcs loops from:

   1)
   i = 0 to 5  // the 6 parameters
   j = 0 to 5

   to

   2)
   i = 0 to 5
   j = i to 5

   because in 1) the i-j and j-i are counted twice, except for i-i,
   so it is not correct to then simply divide by 2.
   in 2) the i-j are counted singly, even for i-i.

   Regards,
   Marc.

//--------------------------------------------
Marc Parisien
parisien@iro.umontreal.ca
www-lbit.iro.umontreal.ca



Further note from Marc Parisien:

From parisien@iro.umontreal.ca Wed May 11 23:16:48 2005
Date: Tue, 19 Apr 2005 08:54:46 -0400 (EDT)
From: Marc Parisien <parisien@iro.umontreal.ca>
To: Bruno Contreras Moreira <contrera@ccg.unam.mx>
Cc: xiangjun@rutchem.rutgers.edu
Subject: Re: help with DNA deformation energy

Hi Dr. Bruno,


> I've just found your deformation energy code at
> http://rutchem.rutgers.edu/~xiangjun/3DNA
Cool!


> What's the energy reported? is it the energy that you need to apply to the
> system to obtain a given DNA deformation with a given sequence?
It is a deformation energy (units are kcal/mol, I think) based on
population preferences: E = -RT ln( P ) where P is the probability of
finding the sample in that conformation. This deformation energy reaches
back to Go where he analyzed the protein helix deformations (I don't
have that reference). I suggest that you imperatively read the 2 articles
mentionned in the "credits" section of the program (in the main()
routine).


> Do you need full-detail PDB coordinates of the DNA or the backbone is enough?
> Thanks for your feedback and for the code!!
Unfortunately, you need the full DNA since the energies come from the
side-chain conformations. You will have to launch the 3DNA program before
calculating the energies.


The energies reported here are not to be confused with those reported by
force-fields like AMBER or CHARMM... the energies here are those only from
population samples! You would have to do a thermodynamic cycle to obtain
the energy to apply to the system to obtain a given DNA deformation with a
given sequence!


As an application of this program you can look at a DNA/Protein complex
and do in-silico DNA mutations by changing the nature of the nucleotides
but without modifying the DNA 3D structure... You can then select the best
DNA sequence for that particular DNA 3D structure...


Do not mix the 2 energies calculations: use my program with the "-s"
option (the step energy) or with "-b" (the base-pairs energy)...



    Regards,
      Marc.

//--------------------------------------------
Marc Parisien
parisien@iro.umontreal.ca
www-lbit.iro.umontreal.ca



1296
Users' contributions / Building modified fiber models
« on: January 07, 2012, 11:26:32 pm »
This post is based on a series of email exchanges I had with Satoshi Yokojima (Institute of Materials Science, University of Tsukuba, Japan) in June 2004. This topic is on how to build base-only fiber models with varying rise, using a combination of various 3DNA components. Satoshi Yokojima kindly summarized the procedure from a user's perspective, as enclosed below.

-- Xiang-Jun
From yokojima@adenine.ims.tsukuba.ac.jp
Date: Fri, 25 Jun 2004 21:32:13 +0900 (JST)
From: Satoshi Yokojima <yokojima@adenine.ims.tsukuba.ac.jp>
To: Xiangjun LU <xiangjun@rutchem.rutgers.edu>
Cc: W. K. Olson <olson@rutchem.rutgers.edu>,
     Satoshi Yokojima <yokojima@adenine.ims.tsukuba.ac.jp>
Subject: Re: 3DNA --- building "modified" fiber models

Dear Dr. Lu:

I have finished the check of the new geometry and I found that
it is what I wanted to have.  The procedure you have suggested
worked nicely.  The thing what I did is as follows:

 [1] A new directory X3DNA/MY_Fiber55 is created.
 [2] The A|C|G|T.pdb files are copied from X3DNA/FIBER/Str55
    into X3DNA/MY_Fiber55.
 [3] In order to rebuilt the structure without backbones,
    I have deleted the backbone atoms from A|C|G|T.pdb
    using vi.
 [4] The following commands are executed in X3DNA/MY_Fiber55.
         > std_base A.pdb Atomic_A.pdb
         > std_base C.pdb Atomic_C.pdb
         > std_base G.pdb Atomic_G.pdb
         > std_base T.pdb Atomic_T.pdb
 [5] A new directory test/rise=10 is created where I wanted to
    produce the 55-th fiber model structure without the
    backbone and with Rise = 10 Angstrom.
 [6] The files Atomic_A|C|G|T.pdb are linked to the directory
    test/rise=10.
 [7] The 55-th fiber model structure 5'-GG-3' is generated in
    the directory test/rise=10 by the command:
         > echo "2"   > f55.in
         > echo "GG" >> f55.in
         > echo "1"  >> f55.in
         > fiber -55 f55.pdb < f55.in >& f55.out
 [8] The following command is executed.
         > find_pair f55.pdb stdout | analyze
 [9] The Rise value in the file "bp_step.par" is modified
    to 10 Angstrom by vi editor.
[10] The 55-th fiber model structure without the backbone
    and with Rise = 10 Angstrom is created by the command
    rebuild as follows:
         > rebuild -atomic bp_step.par f55_newRise.pdb
[11] The procedure from [5]-[10] is repeated for the different
    Rise values.

I think it is a good idea to add a lot of examples in the manual.
People can learn much easier from the casebook than from the
explanation of the commands.  I did not even imagine that the 3DNA
can do some of these things.  Also, if you have a good manual,
I can recommend other people to use 3DNA to build DNA structures.

It is very kind of you to explain the detailed usage of 3DNA.
Thank you very much, again.

 Sincerely yours,
 Satoshi Yokojima

    --------------------------------------
              Satoshi  Yokojima
      yokojima@adenine.ims.tsukuba.ac.jp
        Institute of Materials Science
            University of Tsukuba
    --------------------------------------

On Fri, 25 Jun 2004, Satoshi Yokojima wrote:

> Dear Dr. Lu:
>
> Thank you very much for your quick reply.  It looks like it is
> working this time, but I think I need to do more careful check
> tomorrow.  I will send you another e-mail when I finish doing it.
>
> Thank you very much, again.
>
>  Sincerely yours,
>  Satoshi Yokojima
>
>     --------------------------------------
>               Satoshi  Yokojima
>       yokojima@adenine.ims.tsukuba.ac.jp
>         Institute of Materials Science
>             University of Tsukuba
>     --------------------------------------
>
> On Thu, 24 Jun 2004, Xiangjun LU wrote:
>
> > Dear Satoshi:
> >
> > Thanks for your message. I am so glad you noticed this slight difference.
> > Apparently, you are a rigorous scientist by not taking your tools blindly.
> >
> > The reason for this slight difference is due to the fact that the standard
> > default base geometry (Atomic_A|C|G|T.pdb under X3DNA/BASEPARS) used by
> > 3DNA when rebuilding the structure is DIFFERENT from the geometry of the
> > fiber model 55 repeating units.
> >
> > Using a different set of base geometry for analysis and rebuild is
> > expected when we developed 3DNA, and the solution to your problem would be
> > as follows:
> >
> > [1] create a new directory, say MY_Fiber55
> > [2] copy into MY_Fiber55 the A|C|G|T.pdb files from X3DNA/FIBER/Str55
> > [3] Since you would like the rebuilt structure WITHOUT backbones, you need
> >     to delete the backbone atoms from A.pdb etc manually, using any text
> >     editor (e.g., vi or emacs)
> > [4] run command
> >               std_base A.pdb Atomic_A.pdb
> >       and repeat the above for C.pdb, G.pdb and T.pdb
> > [5] Then `analyze', change Rise in "bp_step.par", and `rebuild' as
> >     outlined previously, the "slight difference between the required and
> >     produced structure" will be gone.
> >
> > Type "std_base" for more help information. Another issue to note here is
> > that `analyze' and `rebuild' check for standard base geometry files from
> > current working directory first, then those defined by environmental
> > variable X3DNA, and finally ~/X3DNA.
> >
> > Please have a try and let me know what happens. It would help if you could
> > document step-by-step what you did. We are currently working to improve
> > documentations on 3DNA, and we certainly welcome users working examples.
> > Of course, we will properly acknowledge your contributions.
> >
> > Best regards,
> >
> > Xiang-Jun
> >
> > On Thu, 24 Jun 2004, Satoshi Yokojima wrote:
> >
> > > Dear Dr. Lu:
> > >
> > > After examining the file produced by the method you have suggested,
> > > I have noticed that there is a slight difference between the required
> > > and produced structure.  The difference is in, for example, the bond
> > > length.
> > >
> > >   I wanted to keep all the structural parameters in the 55-th
> > > fiber model but Rise.  It means I need to use the bond length and
> > > angles (including Hydrogen-bond) found in the 55-th fiber model.
> > > This is important because the 0.1 Angstrom difference of the bond
> > > length changes the single bond to the double bond.  Therefore, the
> > > results of the electronic structure calculations are quite different.
> > >
> > >   Are there any method I can use to make 3DNA produce the structure
> > > I want to have?  Somewhat hard way, such as replacing BASEPAIR files,
> > > is fine for me, but I need to know what is the correct way to do it.
> > >
> > >  Sincerely yours,
> > >  Satoshi Yokojima
> > >
> > >     --------------------------------------
> > >               Satoshi  Yokojima
> > >       yokojima@adenine.ims.tsukuba.ac.jp
> > >         Institute of Materials Science
> > >             University of Tsukuba
> > >     --------------------------------------
> > >
> > >
> > > On Thu, 24 Jun 2004, Satoshi Yokojima wrote:
> > >
> > > > Dear Dr. Lu:
> > > >
> > > > Thank you very much for your detailed explanation about the coordinates
> > > > used in the fiber model.  Your suggested method to make the 55th fiber
> > > > model without a backbone and a different Rise value works perfectly.
> > > > That was just what I wanted to know.
> > > >
> > > > Thank you very much, again.
> > > >
> > > >  Sincerely yours,
> > > >  Satoshi Yokojima
> > > >
> > > >     --------------------------------------
> > > >               Satoshi  Yokojima
> > > >       yokojima@adenine.ims.tsukuba.ac.jp
> > > >         Institute of Materials Science
> > > >             University of Tsukuba
> > > >     --------------------------------------
> > > >
> > > > On Wed, 23 Jun 2004, Xiangjun LU wrote:
> > > >
> > > > > Dear Satoshi:
> > > > >
> > > > > Thanks for using 3DNA and your nice words about it.
> > > > >
> > > > > Now, to answer your questions. Firstly, all the fiber models are based on
> > > > > literature work. Under directory X3DNA/FIBER, there is a README file, and
> > > > > a subdirectory for each of the 55 fiber models inlcuded with 3DNA. For the
> > > > > 55th fiber model, for example, you will find the following files at Str55/
> > > > >
> > > > > ----------------------------------------------------------
> > > > >     A.pdb      C.pdb      G.pdb      T.pdb
> > > > >     A.rpt      C.rpt      G.rpt      T.rpt
> > > > >     TableIV.dat
> > > > > ----------------------------------------------------------
> > > > >
> > > > > File "TableIV.dat" contains the data originally published by the authors.
> > > > > In this case, S. Premilat & G. Albiser "Conformations of A-DNA and B-DNA
> > > > > in agreement with fiber X-ray and infrared dichroism."  Nucleic Acids
> > > > > Research, 11(6), (1983), p.1897-1908.
> > > > >
> > > > > A|C|G|T.rpt are the processed files in "pseudo"-PDB format, actually
> > > > > storing atomic cylindrical coordinates. These repeating units are used by
> > > > > 3DNA to generate the fiber models given a base sequence or the number of
> > > > > repeats. The corresponding *.pdb files are in real PDB format with the
> > > > > corresponding x-, y-, and z-coordinates converted from the cylindrical
> > > > > coordinates. These PDB files can be displayed using a molecular graphics
> > > > > program, such as Rasmol. While they are not directly used by 3DNA while
> > > > > generating the fiber models, they were helpful for "quality-control" in
> > > > > the initial process.
> > > > >
> > > > > The 55 fiber model collected in 3DNA are from different authors, spanning
> > > > > several decades. Quite naturally, file formats, conventations for z-axis
> > > > > directions, atomic names etc, varied greatly, and of course, with typos,
> > > > > errors as well. To provide a useful tool to the community, we went through
> > > > > some quite painstaking procedures to make our collection as transparent
> > > > > and consistent as possible.
> > > > >
> > > > > Secondly, with the above background information, and if I understand your
> > > > > question accurately, i.e. you would like a model based on fiber #55,
> > > > > without the backbone and a different Rise value. This could be easily done
> > > > > in 3DNA as follows:
> > > > >
> > > > > [1] generate the 55-th fiber model using any base sequence you are
> > > > >     interested in, say named f55.pdb
> > > > > [2] find_pair f55.pdb stdout | analyze
> > > > > [3] modify file "bp_step.par" or "bp_helical.par" generated by [2] using
> > > > >     your favored text editor by changing the Rise values
> > > > > [4] rebuild -atomic bp_step.par f55_newRise.pdb
> > > > >
> > > > > Hope this helps.
> > > > >
> > > > > Xiang-Jun
> > > > >
> > > > > On Thu, 24 Jun 2004, Satoshi Yokojima wrote:
> > > > >
> > > > > > Dear Dr. Lu:
> > > > > >
> > > > > > I am using your program 3DNA.  Thanks to your nice work,
> > > > > > it is very useful for my research.
> > > > > >
> > > > > > Recently, I wanted to make the 55-th fiber model structure
> > > > > > but without backbone and give different Rise for an analysis
> > > > > > of the energetics of DNA.  Since I cannot do such a thing
> > > > > > by 3DNA as far as I understand, I tried to make a simple
> > > > > > program to do it.
> > > > > >  Then, I have noticed that I do not understand the frame well.
> > > > > > At first, I thought that the i-th local base-pair frame should
> > > > > > be used as a coordinate system to find Shift, Slide, Rise
> > > > > > between the i-th and (i+1)-th base-pairs translation.  However,
> > > > > > it looks like it is not the case.  Now I think that the helical
> > > > > > axis is taken as the z-direction of the coordinate system but
> > > > > > that's not enough for me to determine your coordinate system.
> > > > > >
> > > > > > Could you kindly explain how you have taken the coordinate system
> > > > > > in 3DNA to calculate Shift, Slide, Rise.  If it is not so easy,
> > > > > > could you tell me any reference?
> > > > > >
> > > > > > Thank you very much in advance.
> > > > > >
> > > > > >  Sincerely yours,
> > > > > >  Satoshi Yokojima
> > > > > >
> > > > > >     --------------------------------------
> > > > > >               Satoshi  Yokojima
> > > > > >       yokojima@adenine.ims.tsukuba.ac.jp
> > > > > >         Institute of Materials Science
> > > > > >             University of Tsukuba
> > > > > >     --------------------------------------
> > > > > >
> > > > >
> > > >
> > >
> >
>

1297
Hi Difei,

Thanks for posting your question in the new 3DNA forum!

You've raised a very subtle, yet interesting and significant point w.r.t. to find_pair. There are several aspects to address the issue you experienced, as follows:

  • There is actually one more (undocumented) 'sanity' check for base pair than those specified in the file 'misc_3dna.par': the overlap area between the two bases. The current fixed setting is 0.01 Å2, i.e., virtually allowing for no overlap. The 'missing pairs' in the two sample structures all have overlap areas over the criterion, which explains why you cannot find it by manipulating the various parameters in 'misc_3dna.par'. See attached figure for the pair A12_G with B13_C in 'md5.1004.mod.pdb' you emailed me.
  • From my understanding of the term, I certainly won't classify such extreme cases as base pairs: base-overlapping is associated with stacking (vertical) instead of pairing (plannar). That's why I've not documented this criterion, but internally checked for it.
  • To 'force' such pairs, it is best to first run find_pair on the structure (or a representative from an ensemble) and then make manual changes as necessary. The analysis routines in 3DNA, analyze/cehs, will calculate relevant parameters accordingly (indeed, of any arbitrary pair). The topic has shown up repeatedly in the forum, especially with regard to the analysis of NMR ensemble or MD trajectories. See the section "Molecular dynamics simulations".
  • To allow for more flexibility,  it may be desirable (at least won't hurt) to have the overlap criterion also available in 'misc_3dna.par'. Do you want to try this? If so, please let me know your OS so I can provide you a test version.

HTH,

Xiang-Jun

1298
Feature requests / Re: Align multi-model (NMR) structures
« on: December 30, 2011, 01:34:31 pm »
The various ensemble related scripts will be consolidated in the coming v2.1 release.

Xiang-Jun


P.S. Did you know that one can click 'Notify' to receive email notification when a new post becomes available in a thread or forum you are interested in? It is a cool feature -- now I can be alerted with every new post or registration.

1299
Feature requests / Re: Align multi-model (NMR) structures
« on: December 28, 2011, 09:09:44 pm »
Hi Andrew,

Thanks for this feature request and for providing two sample images -- it would indeed make a nice feature for future release of 3DNA. There are many things I would like to consolidate/refine, and new features to add! This requested feature fits nicely to the overall scheme I have in mind.

Before I can get something for an "official" release of 3DNA v2.1 with this new feature included, I will try to come up with a Ruby script this week for you to try out.

Now to a specific point related to the procedure your outlined:

Quote
I have a suggestion on a new feature for multi-model NMR files, some sort of alignment command to align on each model's reference frame.  I performed this by hand as an example using the following

- Split the multi-model file into individual pdb files, 1 for each model
- for each model...
  - find_pair on the structure
  - rotate_mol using the ref_frame.dat file from find_pair

The pairing is consistent in all of the models but we have to run find_pair on each structure in order to get the reference frame data.

As with the MD simulation analysis script ('x3dna_md.rb'), it would be best for a user to specify the base pairing information. Thus the program 'find_pair' does not need to be run with each model. This would ensure consistency in all the models. Instead, the model-specific 'ref_frame.dat' can be generated with 'analyze'.

Check back ...

Xiang-Jun

1300
I certainly should have made such cases more explicit -- I will add a new section to the forum, titled "Bug reports and feature requests", by the end of the week. As I am working on improving 3DNA, do you have any desired features or suggestions to make the software more useful? Do not be shy!

Xiang-Jun

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Created and maintained by Dr. Xiang-Jun Lu [律祥俊] (xiangjun@x3dna.org)
The Bussemaker Laboratory at the Department of Biological Sciences, Columbia University.