Messages

1

RNA structures (DSSR) / Re: Can x3dna-dssr correctly handle N1-methyl-pseudouridine?

« on: Yesterday at 06:17:34 pm »

Hi Di,

Thanks for the detailed response. I can only wish that all users are just like you in providing such helpful feedback. Over the years, it is users like you who have motivated me to keep working on DSSR ...

Best regards,

Xiang-Jun

2

General discussions (Q&As) / MOVED: Rebuilding circular Z-DNA

« on: Yesterday at 12:14:22 pm »

This topic has been moved to RNA structures (DSSR).

http://forum.x3dna.org/index.php?topic=1045.0

3

RNA structures (DSSR) / Re: Rebuilding circular Z-DNA

« on: Yesterday at 12:13:54 pm »

Hi Di,

Thanks for chiming in on the topic on modeling Z-DNA structures with proper backbones. User @shr "would also look forward to Z-DNA backbones being included in DSSR modeling functionalities."

Let's continue the discussion through this thread. Your special interest in circular Z-DNA structures will also be taken into account.

In addition to splitting the topic as a new thread, I have also moved the thread under the Section on RNA structures (DSSR) from "General discussions (Q&As)". I aim to develop this feature within DSSR. As noted previously, the classic 3DNA suite of programs has been superseded by DSSR.

If you and @shr could share what you have done so far, I would very much like to see. The more concrete examples, the better.

Best regards,

Xiang-Jun

4

RNA structures (DSSR) / Re: Can x3dna-dssr correctly handle N1-methyl-pseudouridine?

« on: Yesterday at 12:01:47 pm »

Hi Di,

As a follow-up to my previous response to your question, I have just written up a blog post on this topic: See Mapping of modified nucleotides in DSSR. In particular, from the listed ANSI C code, you should find the answer on how DSSR uses atomic connectivity to decide on pseudouridine modifications.

Best regards,

Xiang-Jun

5

General discussions (Q&As) / Re: Rebuilding Z-DNA

« on: Yesterday at 09:57:23 am »

Apologies for it took a while to reply. Thank you for your help with the structure! I used phenix to minimise like you suggested and I can use it for my analysis now.

Thanks for the confirmation that the DSSR modeled Z-DNA structure works for your case. It is through interactions with real-world users like you that makes DSSR relevant and useful.

Even though virtual, a forum thread is just like a conversation. I strive to respond to users' questions timely and concretely. Users who initiate a thread are expected to follow up with their progress and share their findings, or the lack thereof. It’s a two-way street, and I appreciate your engagement and contributions to the forum.

As a follow up, I am planing to write a blogpost to summarize the discussion and provide step-by-step details on how the extended Z-DNA structure was built using DSSR. This may take a couple of days, and I will provide a link here once it is ready.

I would also look forward to Z-DNA backbones being included in DSSR modeling functionalities.

I have split a new thread titled "Rebuilding circular Z-DNA". Please share your thoughts and suggestions on this topic over there.

Best regards.

Xiang-Jun

6

RNA structures (DSSR) / Re: Can x3dna-dssr correctly handle N1-methyl-pseudouridine?

« on: Yesterday at 09:08:26 am »

Hi Di,

Thanks for your well formulated question regarding x3dna-dssr’s support of N1-methyl-pseudouridine, B8H.

I understand that x3dna-dssr can handle pseudouridine (PDB Chem ID: PSU) correctly. I'm inquiring about its support for N1-methyl-pseudouridine (PDB Chem ID: B8H). Specifically,​ does x3dna-dssr recognize B8H based on its PDB chemical ID, or does it rely on atomic connectivity?

FYI, I've tested x3dna-dssr with PDB entries 8PFK and 8PFQ, both containing B8H, and the analysis proceeded without errors, with the results looking reasonable. However, given the unique C5-C1′ glycosidic bond for B8H, I want to confirm that x3dna-dssr interprets this modification accurately.

DSSR uses atomic connectivity to identify pseudouridine or its modified forms, including B8H. DSSR User Manual contains the following relevant information:

Note that pseudouridine, the most prevalently modified nt in RNA, is denoted P† in DSSR and the small case p is reserved for potential modified pseudouridines. ... footnote: †Not to be confused with the phosphorus atom in the backbone phosphate group. The distinction should be clear in context.

While anticipated, your reported case of B8H is the first time I see a modified pseudouridine. In DSSR output for 8PFK, you will see the following:

Code: Text

1. #x3dna-dssr -i=8PFK.pdb -o=8PFK.out
2.  
3. From 8PFK.out
4. ****************************************************************************
5. List of 1 type of 1 modified nucleotide
6.       nt    count  list
7.    1 B8H-p    1    A.B8H7
8.  
9. From dssr-torsions.txt
10. 7     p A.B8H7 ... chi -155.3(anti)

The chi for B8H is defined using O4'--C1'--C5--C4 instead of O4'--C1'--N1--C2, which would make no sense for pseudouridine. This is a little detail that DSSR pays attention to where other tools may not. See my blogpost Torsion angles from DSSR. You could easily verify this, using PyMOL for example, to measure the torsion angle by clicking four atoms in order.

The DSSR results for 8PFQ are also as expected with correct identification of B8H as a modified pseudouridine.

Further, is there a comprehensive list of modified nucleotides currently supported by x3dna-dssr?​ I came across these two pages (https://x3dna.org/highlights/automatic-identification-of-nucleotides ; https://x3dna.org/highlights/modified-nucleotides-in-the-pdb ), but could not find the exact answer.

To answer your question, here is an excerpt from my recent response to a similar inquiry:

Over the years, I've refined the heuristics of the mapping process. In the early days with 3DNA, I kept an ever increasing list of 'baselist.dat' with hundreds of entries like: MIA   a that maps MIA as a modified A, denoted as lowercase 'a'. In the current DSSR, I keep only the standard ones, with 48 entries total (see attached DSSR-baselist.txt). If a residue is not a standard one, the following function is called to do the mapping (DSSR performs filtering to decide if it is a nucleotide, and if so R or Y). DSSR also has a command-line option --nt-mapping as documented in the screenshot.

The DSSR-baselist.txt is attached for your reference. I am planning to write blogpost with details on this topic.

Best regards,

Xiang-Jun

7

General discussions (Q&As) / Re: Rebuilding Z-DNA

« on: April 21, 2025, 04:20:23 pm »

Hi,

Thanks for chiming in on the discussion. Currently, DSSR can build DNA circles with right-handed helices, but not Z-DNA forms. The backbone of Z-DNA is dramatically different from that of B-DNA or A-DNA, and needs to be modeled differently. I'll look into how we can incorporate Z-DNA backbones into DSSR modeling functionalities, given enough interest from the community, and with a proper collaborator to work on it. See the DSSR-Jmol and DSSR-PyMOL integration for two concrete examples of what I have in mind for such collaborations.

As for the current thread, I'm hoping @shr could respond to my question on March 15, 2025:

Does the attached PDB file (with base schematic image) fulfill your needs?

See my recent post On registration and posting which includes a copy of "Registration Agreement for the Forum" at the bottom.

Best regards,

Xiang-Jun

8

Site announcements / On registration and posting

« on: April 19, 2025, 11:20:25 pm »

It has been 14 years since the Forum was created in 2011. Despite a four-year gap in NIH funding, we managed to keep the Forum operational. Maintaining and nurturing our community wasn't easy, but the users' enthusiasm in using and citing 3DNA/DSSR has kept us going. With the dedicated R24GM153869 grant, I am now committed to making the Forum even better.

Keeping the Forum spam-free is our top priority. In recent months, we have seen a dramatic increase in spams, which account for the majority of new registrations. That is why we have implemented 'Admin Approval' as the method of registration for new members. I carefully review each new registration to ensure only legitimate users are approved to join the Forum. Once approved, new users need to activate their accounts by clicking the activation link sent to their registered email address. I have noticed that some users did not activate their accounts upon approval. I normally send reminders to those inactivated users, but if they still do not respond in a few days, their registrations will be removed from the Forum.

It could also be the other way around: for example, the activation email sent from the 3DNA Forum might have been filtered out as spam by the user’s email agent. I have recently helped a few users with their registrations. If you have any questions or concerns about your registration, feel free to reach out to me directly via email. In today's age of AI, a personal touch goes a long way. Getting assistance directly from the developer ensures issues are resolved quickly and effectively.

I am dedicated to continuously enhancing X3DNA-DSSR, aiming to build it as a reputable brand symbolizing quality and value. Due to its exceptional functionality, ease of use, and direct support from the developer, X3DNA-DSSR significantly reduces the time and effort required compared to alternative solutions. Your comments, suggestions, and bug reports are greatly appreciated; I carefully consider every piece of user feedback, and always respond promptly. Specifically, I encourage you to openly share any challenges or negative experiences you encounter during installation or usage. Asking your questions on the public 3DNA Forum benefits not only yourself but also the wider user community.

Enclosed below is the Registration Agreement for the Forum

This forum is dedicated to topics generally related to the X3DNA-DSSR resource for the analysis, rebuilding, and visualization of 3D nucleic acid structures. To make the Forum a pleasant virtual community for all of us to learn from and contribute to, please be considerate and practice good netiquette (http://www.albion.com/netiquette/). See also the FAQ entry "How to make the best use of the Forum".

I strive to make the Forum spam free. Private emails (gmail.com, yahoo.com, qq.com, rambler.ru etc.) are not accepted; such registrations will be removed. Approved registrations that are not activated via email will be deleted. Activated accounts that are not accessed (logins) will be erased. Posts that are not 3DNA/DSSR related in the broad sense are taken as spams and are strictly forbidden. All administrative actions are performed without notification.

DSSR has completely superseded 3DNA (which is still maintained, but no new features other than bug fixes). DSSR integrates the disparate programs of 3DNA under one umbrella, and offers new advanced features, through a convenient interface. DSSR requires no set up or configuration: it just works. See the Overview Video and User Manual.

When posting on the Forum, please abide by the following rules:

0.  Do your homework; read the FAQ and browse the Forum.
1.  Ask your questions on the *public* 3DNA Forum instead of sending
        xiangjun emails or personal messages. Additionally, please note
        that your posts on the 3DNA Forum are in the *public domain*.
2.  Be specific with your questions; provide a minimal, reproducible
        example if possible; use attachments where appropriate.
3.  Respond to requests for clarification. Failure to do so may result in
        delay or no answer to your questions.
4.  Summarize the solution to your problem from a user's perspective
        by providing step-by-step details, for the community's benefit.
5+ Contribute back to the 3DNA project:
        o Report bugs — including typos
        o Make constructive suggestions — anything that can make 3DNA better
        o Answer other users' questions
        o Share your use cases in the "Users' contributions" section

In a nutshell, you are welcome to participate and should not hesitate to ask questions, but remember to play nice and preferably share what you learned! Please note that we do *not* tolerate spamming or off-topic trolling of any form.

9

Site announcements / Re: Download instructions

« on: April 19, 2025, 10:06:06 pm »

Only 3DNA v2.4.8-2023nov10 is available for download. The ANSI C source code and Ruby scripts are included in the package, along with precompiled binaries for Linux and macOS. The Linux version should also work under Windows using WSL2. In any case, you can compile the source code easily as long as you have a C compiler installed on your system.

10

General discussions (Q&As) / Re: Rebuilding Z-DNA

« on: March 17, 2025, 09:18:59 am »

But I am unable to properly download the pdb file.

What do you mean? Just click on the link and it should download automatically. I've never heard of any issues with downloading files as long as you have an active internet connection. Please clarify your issue so I can assist you better.

11

General discussions (Q&As) / Re: Rebuilding Z-DNA

« on: March 15, 2025, 12:18:44 am »

Does the attached PDB file (with base schematic image) fulfill your needs? The backbone connection between the two segments are a bit longer than normal O--P covalent bond distance, which you can regulated with energy minimizations (e.g., using Phenix, as shown in "Web 3DNA 2.0 for the analysis, visualization, and modeling of 3D nucleic acid structures" (https://doi.org/10.1093/nar/gkz394).

12

General discussions (Q&As) / Re: Rebuilding Z-DNA

« on: March 14, 2025, 08:12:34 am »

Thanks for your follow-up questions and the details you provided. It is always helpful to to be specific when discussing research topics.

Yes, "rebuild -atomic" would have issues with backbone connectivity, since in Z-DNA, nucleotide G is in syn conformation instead of anti (for C). The building block must be adjusted accordingly. I'll look into this further to see what we can get.

Another approach is to take the whole Z-DNA structure as a unit, and perform some transformations to extend it. See the PyMOL thread a few years ago on "create a 26 bp RNA from a 13 bp system" (https://www.mail-archive.com/pymol-users@lists.sourceforge.net/msg16190.html). The idea is applicable to Z-DNA as well. Note that the features are now available in the free DSSR Academic license (previously in DSSR Pro Academic only). Check if that method makes sense to you.

Best regards,

Xiang-Jun

13

General discussions (Q&As) / Re: Rebuilding Z-DNA

« on: March 13, 2025, 03:56:04 pm »

Thanks for your quick follow-up.

As noted in the x3dna_utils cp_std -h help message, the utility covers the most common use cases:

Select the standard data files to be used with "analyze" and "rebuild".
Available sets include BDNA, ADNA, NDB96 and RNA, which have exactly
the same base geometry and orientation (in the standard base reference
frame) but different backbone conformations.

Z-DNA is different from the standard right-handed DNA/RNA double helix in that it has not only a left-handed twist but also a base flip, and it has a di-nucleotide (most commonly CpG) as a the building block. So the x3dna_utils cp_std does not cover Z-DNA. However, you can run analyze, modify the output parameters (and extend as needed), and then rebuild a Z-DNA structure according to the modified parameters.

What specific Z-DNA structure you’d like to extend? If you do not want share details, please use a sample Z-DNA structure that helps illustrate your point. Reproducibility is important.

Best regards,

Xiang-Jun

14

General discussions (Q&As) / Re: Rebuilding Z-DNA

« on: March 13, 2025, 02:14:06 pm »

Hi,

Thanks for using 3DNA and for posting your questions on the Forum. 3DNA rebuild should be able to build Z-DNA structures given a set of parameters. Please be specific with what you are trying to achieve, and we can start from there.

Best regards,

Xiang-Jun

15

General discussions (Q&As) / Re: Generation of ssDNA PDB with m3C modification using 3DNA webserver

« on: February 28, 2025, 08:47:06 am »

Welcome back.

But I do not have a PDB structure with the m3C modification, I was hoping that we would be able to generate the PDB (and PSF) using 3DNA/DSSR by specifying the residues.

Are you expecting 3DNA/DSSR to "generate the PDB" by specifying the residues, including unknown ones?  3DNA/DSSR can build DNA/RNA structures with standard bases (A,C,G,T,U), or modified ones with *known* building block as illustrated in 5-methylcytosine in the FAQ. It does not generate structures for ligands like m3C. It is up to the user to provide such building blocks for 3DNA/DSSR to proceed. CCP4 and Phenix may have utilities to generate new ligands.

By the way, what does PSF stand for?

As a side question, what would be a good force field that can allow us to perform a phase separation simulation with the methylated ssDNA and IDR sequence?

Sorry, I'm not familiar with this field, and I cannot offer any valuable suggestions. Overall, this question is out of the scope of the Forum.

Best regards,

Xiang-Jun

16

MD simulations / Re: Update of do_x3dna package

« on: February 22, 2025, 11:23:27 pm »

Hi Rajendra,

Thanks for the update to do_x3dna for GROMACS-2025. It is great that the "binary package can be used with files generated by any version of GROMACS". Over the years, I've received emails about applying 3DNA to MD simulations, and I know that your do_x3dna package is well received by the community.

Best regards,

Xiang-Jun

17

General discussions (Q&As) / Re: Opening values and the definition for base-pair parameters

« on: February 07, 2025, 10:22:26 am »

Hi Jing,

Please follow what I suggested in the previous response. As for the 3DNA source code, did you notice the download link at the top and the Download instructions post?

Best regards,

Xiang-Jun

18

General discussions (Q&As) / Re: Opening values and the definition for base-pair parameters

« on: February 06, 2025, 11:14:10 am »

Hi Jing,

I have attached several pictures here. They are G and G pairs. The first two are with the opening \~180, the third picture is with \~-180, and the last two are with \~90.

Thanks for your follow up, and for providing images that illustrate G.G pairs with opening around 180 and 90 degrees. It would have been more helpful if you attached the corresponding PDB files. When posting questions in the future, thinks about providing (mininal) examples so others can *reproduce* the cases.

Now I understand the question you're asking. Let's use a G+G pair in G-tetrad of G-quadruplexes as an example, which has an opening around 90 degrees. Assuming you have downloaded the coordinates file `5ua3.pdb` for PDB entry 5ua3 on "Crystal structure of a DNA G-quadruplex with a cytosine bulge". Please try the following DSSR commands:

Code: [Select]

# This extract DG1 and DG6 from chain A into file 5ua3-GG.pdb
x3dna-dssr -i=5ua3.pdb --select-residue='A 1+6' -o=5ua3-GG.pdb

# Set the pair into the base reference frame of A.DG1
x3dna-dssr -i=5ua3-GG.pdb --frame='A.1' -o=5ua3-GG-frame1.pdb

# Generate the schematic with base blocks
x3dna-dssr -i=5ua3-GG-frame1.pdb --cartoon-block=sticks-label --block-file=slim-outline -o=5ua3-GG-frame1.pml
Load `5ua3-GG-frame1.pml` into PyMOL to see the attached image where the (`slim`) base blocks are nearly perpendicular, corresponding to an opening angle of ~90 degrees.

Analyze `5ua3-GG.pdb` (or `5ua3-GG-frame1.pdb`) with `--more` option to see the six base-pair parameters, including opening.

Code: [Select]

x3dna-dssr -i=5ua3-GG.pdb --more

# With the following detailed information:
List of 1 base pair
     nt1            nt2            bp  name        Saenger   LW   DSSR
   1 A.DG1          A.DG6          G+G --          06-VI     cWH  cW+M
       [-131.0(anti) ~C2'-endo lambda=62.6] [-128.4(anti) ~C2'-endo lambda=28.0]
       d(C1'-C1')=11.59 d(N1-N9)=9.65 d(C6-C8)=9.30 tor(C1'-N1-N9-C1')=10.9
       H-bonds[2]: "N1(imino)-O6(carbonyl)[2.95],N2(amino)-N7[2.91]"
       interBase-angle=1  Simple-bpParams: Shear=-2.67 Stretch=2.83 Buckle=-0.8 Propeller=0.5
       bp-pars: [1.61    3.54    -0.15   0.14    0.94    -89.63]
Note that the opening is reported as `-89.63` --- if you try to align A.DG6 to A.DG1, you need to rotate ~`-90` degrees as can be seen in the attached images. If you swap the pair, the opening would be ~`+90` degrees. See the [2003 3DNA paper in NAR](https://doi.org/10.1093/nar/gkg680), specifically the section "Base pair parameters".

With a clear understand of the above example, you should have little difficult in understanding opening ~180 degrees. You are suggested to follow the above example on one of such cases, and report back your findings.

Note that 3DNA/DSSR report angular parameters in the range of [0, +-180] instead of [0, 360]. So opening of `-175` is not that much a difference from `+175` (vs `+185`). Also notice the opposite sign of opening for M+N vs N+M pairs.

Please read the [DSSR manual](http://docs.x3dna.org/dssr-manual.pdf) and the [practical guide for the DSSR-PyMOL](http://skmatic.x3dna.org/dssr-schematic-guide.pdf) article.

Best regards,

Xiang-Jun

19

General discussions (Q&As) / Re: Opening values and the definition for base-pair parameters

« on: February 03, 2025, 06:05:26 pm »

Hi Jing,

Thanks for using 3DNA, and for posting your questions on the Forum. Your confusions about the details are understandable, and can be clarified most effectively using concrete examples. Do you have examples with opening ~90 and 180?

Since 3DNA source code is available, you can dig into it to see exactly how the base reference frames are defined and how the various parameters are calculated.

Best regards,

Xiang-Jun

20

General discussions (Q&As) / Re: Generation of ssDNA PDB with m3C modification using 3DNA webserver

« on: January 31, 2025, 08:51:31 am »

Hi Sunera,

Thanks for your follow up. Is the idea in FAQ "How can I mutate cytosine to 5-methylcytosine?" relevant? Do you have a PDB structure with m3C modification?

Best regards,

Xiang-Jun

21

General discussions (Q&As) / Re: Generation of ssDNA PDB with m3C modification using 3DNA webserver

« on: January 30, 2025, 11:10:45 am »

Hi,

Thanks for your interesting in using 3DNA and for posting your questions on the Forum.

The http://web.x3dna.org has features to build regular fiber models or customized structures (including single-stranded structure as detailed in the supplemental PDF). However, the web-server does not allow you to generate  single-stranded DNA containing a 3-methylated cytosine. The web server simply does not have 'knowledge' of what a 3-methylated cytosine is. I know of no other tools that can do this automatically.

However, 3DNA/DSSR has features that would allow for such modeling from the command line. I need more details of exactly what you want to achieve to be of further help.

See the FAQ: How can I mutate cytosine to 5-methylcytosine?

Best regards,

Xiang-Jun

22

MD simulations / Re: overwritten output files

« on: January 13, 2025, 10:47:57 am »

Hi Mamta,

The output file name is derived from the input PDB filename, by deleting extension and add ".out". Since your PDB frame is named "output-filename.pdb.${i}", the output file will always be "output-filename.pdb.out" by replacing ".{i}" with ".out". You could name your PDB frame "output-${i}.pdb" and the corresponding output file will be "output-${i}.out".

Have a look of the C source code, and the x3dna_ensemble script (x3dna_ensemble analyze -h). Overall, the x3dna-v2.4 support for MD analysis is limited. There is also do_x3dna -- I'm not sure if it is still actively maintained.

I'm in the process of incorporating x3dna-v2.4 features into DSSR (Free academic license available from CTV). Further improvement for MD support will be implemented in DSSR.

Best regards,

Xiang-Jun

23

MD simulations / Re: overwritten output files

« on: January 13, 2025, 08:30:07 am »

Hi Mamta,

Thanks for using 3DNA/DSSR and for posting your question on the 3DNA Forum. Could you please be specific with the command you used? The x3dna-v2.4 suite comes with a Ruby script 'x3dna_ensemble' for analyzing MODEL/ENDMDL delineated ensemble of NMR or MD structures. The x3dna-dssr program has an --nmr (--md) option that streamline the analysis of such ensembles.

Best regards,

Xiang-Jun

24

RNA structures (DSSR) / Re: DNA bend angle

« on: December 30, 2024, 10:49:36 pm »

Hi Narendra,

Thanks for using DSSR and for posting your question on the 3DNA Forum. Regarding DNA bending angle in 3DNA/DSSR, please refer to the FAQ How to calculate DNA bending angle?. With DSSR, the helical axis info is available with the --more option. See the step-by-step procedures for reproducing Figure 2 -- analysis of the yeast phenylalanine tRNA (1ehz) of the 2015 DSSR paper in NAR.

For your specific example of 1fjl, DSSR readily identifies a helix (stem) with details on the helical axis. However, DSSR does not directly provide you a bending angle for reason given in the above mentioned FAQ.

Best regards,

Xiang-Jun

25

Site announcements / DSSR-PyMOL enabled schematics on the covers of the RNA Journal

« on: December 16, 2024, 04:11:24 pm »

Cover image provided by X3DNA-DSSR, an NIGMS National Resource for structural bioinformatics of nucleic acids (R24GM153869; skmatics.x3dna.org). Image generated using DSSR and PyMOL (Lu XJ. 2020. Nucleic Acids Res 48: e74).

See the 2020 paper titled "DSSR-enabled innovative schematics of 3D nucleic acid structures with PyMOL" in Nucleic Acids Research and the corresponding Supplemental PDF for details. Many thanks to Drs. Wilma Olson and Cathy Lawson for their help in the preparation of the illustrations.


May 2025 (link to the source)

Complex of terminal uridylyltransferase 7 (TUT7) with pre-miRNA and Lin28A (PDB id: 8OPT; Yi G, Ye M, Carrique L, El-Sagheer A, Brown T, Norbury CJ, Zhang P, Gilbert RJ. 2024. Structural basis for activity switching in polymerases determining the fate of let-7 pre-miRNAs. Nat Struct Mol Biol 31: 1426–1438). The RNA-binding pluripotency factor LIN28A invades and melts the RNA and affects the mechanism of action of the TUT7 enzyme. The RNA backbone is depicted by a red ribbon, with bases and Watson-Crick base pairs represented as color-coded blocks: A/A-U in red, C/C-G in yellow, G/G-C in green, U/U-A in cyan; TUT7 is represented by a gold ribbon and LIN28A by a white ribbon. Cover image provided by X3DNA-DSSR, an NIGMS National Resource for structural bioinformatics of nucleic acids (R24GM153869; skmatics.x3dna.org). Image generated using DSSR and PyMOL (Lu XJ. 2020. Nucleic Acids Res 48: e74).

April 2025 (link to the source)

Cryo-EM structure of the pre-B complex (PDB id: 8QP8; Zhang Z, Kumar V, Dybkov O, Will CL, Zhong J, Ludwig SE, Urlaub H, Kastner B, Stark H, Lührmann R. 2024. Structural insights into the cross-exon to cross-intron spliceosome switch. Nature 630: 1012–1019). The pre-B complex is thought to be critical in the regulation of splicing reactions. Its structure suggests how the cross-exon and cross-intron spliceosome assembly pathways converge. The U4, U5, and U6 snRNA backbones are depicted respectively by blue, green, and red ribbons, with bases and Watson-Crick base pairs shown as color-coded blocks: A/A-U in red, C/C-G in yellow, G/G-C in green, U/U-A in cyan; the proteins are represented by gold ribbons. Cover image provided by X3DNA-DSSR, an NIGMS National Resource for structural bioinformatics of nucleic acids (R24GM153869; skmatics.x3dna.org). Image generated using DSSR and PyMOL (Lu XJ. 2020. Nucleic Acids Res 48: e74).

February 2025 (link to the source)

Structure of the Hendra henipavirus (HeV) nucleoprotein (N) protein-RNA double-ring assembly (PDB id: 8C4H; Passchier TC, White JB, Maskell DP, Byrne MJ, Ranson NA, Edwards TA, Barr JN. 2024. The cryoEM structure of the Hendra henipavirus nucleoprotein reveals insights into paramyxoviral nucleocapsid architectures. Sci Rep 14: 14099). The HeV N protein adopts a bi-lobed fold, where the N- and C-terminal globular domains are bisected by an RNA binding cleft. Neighboring N proteins assemble laterally and completely encapsidate the viral genomic and antigenomic RNAs. The two RNAs are depicted by green and red ribbons. The U bases of the poly(U) model are shown as cyan blocks. Proteins are represented as semitransparent gold ribbons. Cover image provided by X3DNA-DSSR, an NIGMS National Resource for structural bioinformatics of nucleic acids (R24GM153869; skmatics.x3dna.org). Image generated using DSSR and PyMOL (Lu XJ. 2020. Nucleic Acids Res 48: e74).

January 2025 (link to the source)

Structure of the helicase and C-terminal domains of Dicer-related helicase-1 (DRH-1) bound to dsRNA (PDB id: 8T5S; Consalvo CD, Aderounmu AM, Donelick HM, Aruscavage PJ, Eckert DM, Shen PS, Bass BL. 2024. Caenorhabditis elegans Dicer acts with the RIG-I-like helicase DRH-1 and RDE-4 to cleave dsRNA. eLife 13: RP93979). Cryo-EM structures of Dicer-1 in complex with DRH-1, RNAi deficient-4 (RDE-4), and dsRNA provide mechanistic insights into how these three proteins cooperate in antiviral defense. The dsRNA backbone is depicted by green and red ribbons. The U-A pairs of the poly(A)·poly(U) model are shown as long rectangular cyan blocks, with minor-groove edges colored white. The ADP ligand is represented by a red block and the protein by a gold ribbon. Cover image provided by X3DNA-DSSR, an NIGMS National Resource for structural bioinformatics of nucleic acids (R24GM153869; skmatics.x3dna.org). Image generated using DSSR and PyMOL (Lu XJ. 2020. Nucleic Acids Res 48: e74).

How are the detailed steps used to generate the above cover image, using DSSR v2.4.6-2024nov15:

Code: Bash

1. # Download the PDB structure in cif format from RCSB
2. wget https://files.rcsb.org/download/8t5s-assembly1.cif -O 8t5s.cif
3.  
4. # Run DSSR with the following settings. See below for file "8t5s-specific.pml"
5. x3dna-dssr -i=8t5s.cif \
6.            --blocview=png-session-black \
7.            --block-file=wc-g4 \
8.            --block-depth=1.0 \
9.            --pymol-ray-size=5000 \
10.            --pymol-aa-color=gold \
11.            --block_color="minor:white" \
12.            --cartoon-cmd-file=8t5s-specific.pml \
13.            -o=8t5s.pml
14.  
15. # Run PyMOL to render the image. Here it is from the command line.
16. # You can also load the 8t5s.pml into PyMOL interactively.
17. # Generate file "8t5s-pymol.png"
18. pymol -Qkc 8t5s.pml
19.  
20. # Use ImageMagick to trim extra margins
21. magick 8t5s-pymol.png -trim +repage -bordercolor black -border 120 8t5s.png

Note the setting of black background, and coloring of minor-groove edge in white. By default, DSSR-PyMOL renders with a white background and black minor-groove edges, as in 8t5s. Whenever feasible, I've integrated features into DSSR to automate routine tasks as much as possible.

Here are the related files:

• 8t5s-specific.pml -- specific settings
• 8t5s.pse -- PyMOL session file
• 8t5s.pml -- PyMOL script file
• -- ray-traced image

Moreover, the following 30 [12(2021) + 12(2022) + 6(2023)] cover images of the RNA Journal were generated by the NAKB (nakb.org).

Cover image provided by the Nucleic Acid Database (NDB)/Nucleic Acid Knowledgebase (NAKB; nakb.org). Image generated using DSSR and PyMOL (Lu XJ. 2020. Nucleic Acids Res 48: e74).