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The DSSR-PyMOL schematics have been featured in all 12 cover images (January to December) of the RNA Journal in 2021. Moreover, the January 2022 issue of RNA continues to highlight DSSR-enabled schematics (see the note below). In the current Covid-19 pandemic, this cover seems to be a fit for the upcoming Christmas holiday season.

Ebola virus matrix protein octameric ring (PDB id: 7K5L; Landeras-Bueno S, Wasserman H, Oliveira G, VanAernum ZL, Busch F, Salie ZL, Wysocki VH, Andersen K, Saphire EO. 2021. Cellular mRNA triggers structural transformation of Ebola virus matrix protein VP40 to its essential regulatory form. Cell Rep 35: 108986). The Ebola virus matrix protein (VP40) forms distinct structures linked to distinct functions in the virus life cycle. VP40 forms an octameric ring-shaped (D4 symmetry) assembly upon binding of RNA and is associated with transcriptional control. RNA backbone is displayed as a red ribbon; block bases use NDB colors: A—red, G—green, U—cyan; protein is displayed as a gold ribbon. Cover image provided by the Nucleic Acid Database ( Image generated using DSSR and PyMOL (Lu XJ. 2020. _Nucleic Acids Res_ *48*: e74).

Thanks to Dr. Cathy Lawson at the NDB for generating these cover images using DSSR and PyMOL for the RNA Journal. I'm gratified that the 2020 NAR paper is explicitly acknowledged: it's the first time I've published as a single author in my scientific career.

Did you know that you can easily generate similar DSSR-PyMOL schematics via the website? It is "simple and effective", "good for teaching", and has been highly recommended by Dr. Quentin Vicens (CU Denver) in

The 12 PDB structures illustrated in the 2021 covers are:
  • January 2021 "iMango-III fluorescent aptamer (PDB id: 6PQ7; Trachman III RJ, Stagno JR, Conrad C, Jones CP, Fischer P, Meents A, Wang YX, Ferre-D'Amare AR. 2019. Co-crystal structure of the iMango-III fluorescent RNA aptamer using an X-ray free-electron laser. Acta Cryst F 75: 547). Upon binding TO1-biotin, the iMango-III aptamer achieves the largest fluorescence enhancement reported for turn-on aptamers (over 5000-fold)."
  • February 2021 "Human adenosine deaminase (E488Q mutant) acting on dsRNA (PDB id: 6VFF; Thuy-Boun AS, Thomas JM, Grajo HL, Palumbo CM, Park S, Nguyen LT, Fisher AJ, Beal PA. 2020. Asymmetric dimerization of adenosine deaminase acting on RNA facilitates substrate recognition. Nucleic Acids Res. Adenosine deaminase enzymes convert adenosine to inosine in duplex RNA, a modification that strongly affects RNA structure and function in multiple ways."
  • March 2021 "Hepatitis A virus IRES domain V in complex with Fab (PDB id: 6MWN; Koirala D, Shao Y, Koldobskaya Y, Fuller JR, Watkins AM, Shelke SA, Pilipenko EV, Das R, Rice PA, Piccirilli JA. 2019. A conserved RNA structural motif for organizing topology within picornaviral internal ribosome entry sites. Nat Commun 10: 3629)."
  • April 2021 "Mouse endonuclease V in complex with 23mer RNA (PDB id: 6OZO; Wu J, Samara NL, Kuraoka I, Yang W. 2019. Evolution of inosine-specific endonuclease V from bacterial DNase to eukaryotic RNase. Mol Cell 76: 44). Endonuclease V cleaves the second phosphodiester bond 3′ to a deaminated adenosine (inosine). Although highly conserved, EndoV change substrate preference from DNA in bacteria to RNA in eukaryotes."
  • May 2021 "Manganese riboswitch from Xanthmonas oryzae (PDB id: 6N2V; Suddala KC, Price IR, Dandpat SS, Janeček M, Kührová P, Šponer J, Banáš P, Ke A, Walter NG. 2019. Local-to-global signal transduction at the core of a Mn2+ sensing riboswitch. Nat Commun 10: 4304). Bacterial manganese riboswitches control the expression of Mn2+ homeostasis genes. Using FRET, it was shown that an extended 4-way-junction samples transient docked states in the presence of Mg2+ but can only dock stably upon addition of submillimolar Mn2+."
  • June 2021 "Sulfolobus islandicus Csx1 RNase in complex with cyclic RNA activator (PDB id: 6R9R; Molina R, Stella S, Feng M, Sofos N, Jauniskis V, Pozdnyakova I, Lopez-Mendez B, She Q, Montoya G. 2019. Structure of Csx1-cOA4 complex reveals the basis of RNA decay in Type III-B CRISPR-Cas. Nat Commun 10: 4302). CRISPR-Cas multisubunit complexes cleave ssRNA and ssDNA, promoting the generation of cyclic oligoadenylate (cOA), which activates associated CRISPR-Cas RNases. The Csx1 RNase dimer is shown with cyclic (A4) RNA bound."
  • July 2021 "M. tuberculosis ileS T-box riboswitch in complex with tRNA (PDB id: 6UFG; Battaglia RA, Grigg JC, Ke A. 2019. Structural basis for tRNA decoding and aminoacylation sensing by T-box riboregulators. Nat Struct Mol Biol 26: 1106). T-box riboregulators are a class of cis-regulatory RNAs that govern the bacterial response to amino acid starvation by binding, decoding, and reading the aminoacylation status of specific transfer RNAs."
  • August 2021 "CAG repeats recognized by cyclic mismatch binding ligand (PDB id: 6QIV; Mukherjee S, Blaszczyk L, Rypniewski W, Falschlunger C, Micura R, Murata A, Dohno C, Nakatan K, Kiliszek A. 2019. Structural insights into synthetic ligands targeting A–A pairs in disease-related CAG RNA repeats. Nucleic Acids Res 47:10906). A large number of hereditary neurodegenerative human diseases are associated with abnormal expansion of repeated sequences. RNA containing CAG repeats can be recognized by synthetic cyclic mismatch-binding ligands such as the structure shown."
  • September 2021 "Corn aptamer complex with fluorophore Thioflavin T (PDB id: 6E81; Sjekloca L, Ferre-D'Amare AR. 2019. Binding between G quadruplexes at the homodimer interface of the Corn RNA aptamer strongly activates Thioflavin T fluorescence. Cell Chem Biol 26: 1159). The fluorescent compound Thioflavin T, widely used for the detection of amyloids, is bound at the dimer interface of the homodimeric G-quadruplex-containing RNA Corn aptamer."
  • October 2021 "Cas9 nuclease-sgRNA complex with anti-CRISPR protein inhibitor (PDB id: 6JE9; Sun W, Yang J, Cheng Z, Amrani N, Liu C, Wang K, Ibraheim R, Edraki A, Huang X, Wang M, et al. 2019. Structures of Neisseria meningitidis Cas9 complexes in catalytically poised and anti-CRISPR-inhibited states. Mol Cell 76: 938­–952.e5). Nme1Cas9, a compact nuclease for in vivo genome editing. AcrIIC3 is an anti-CRISPR protein inhibitor."
  • November 2021 "Two-quartet RNA parallel G-quadruplex complexed with porphyrin (PDB id: 6JJI; Zhang Y, Omari KE, Duman R, Liu S, Haider S, Wagner A, Parkinson GN, Wei D. 2020. Native de novo structural determinations of non-canonical nucleic acid motifs by X-ray crystallography at long wavelengths. Nucleic Acids Res 48: 9886–9898)."
  • December 2021 "Structure of S. pombe Lsm1–7 with RNA, polyuridine with 3' guanosine (PDB id: 6PPV; Montemayor EJ, Virta JM, Hayes SM, Nomura Y, Brow DA, Butcher SE. 2020. Molecular basis for the distinct cellular functions of the Lsm1–7 and Lsm2–8 complexes. RNA 26: 1400–1413). Eukaryotes possess eight highly conserved Lsm (like Sm) proteins that assemble into circular, heteroheptameric complexes, bind RNA, and direct a diverse range of biological processes. Among the many essential functions of Lsm proteins, the cytoplasmic Lsm1–7 complex initiates mRNA decay, while the nuclear Lsm2–8 complex acts as a chaperone for U6 spliceosomal RNA."

Site announcements / BioExcel webinar on DSSR
« on: November 23, 2021, 11:38:53 am »
On December 9, 2021, at 15:00 CET, I will present a BioExcel webinar titled "X3DNA-DSSR, a resource for structural bioinformatics of nucleic acids."

For the record, the screenshot of the announcement is shown below:

Site announcements / No more grant funding for 3DNA/DSSR
« on: October 30, 2021, 09:58:15 pm »
Due to a lack of governmental funding support, we are no longer able to provide DSSR free of charge to the community. Academic users may submit a license request for DSSR Basic or DSSR Pro by clicking "Express Licensing". Commercial users may inquire about pricing and licensing terms by emailing, copying

DSSR Pro excels in structural bioinformatics of RNA, DNA, and their protein complexes. The software has completely superseded 3DNA, and is being continuously improved. Revenue from licensing supports the development and availability of DSSR.

I am committed to making DSSR a brand that stands for quality and value. By virtue of its unmatched functionality, usability, and support, DSSR saves users a substantial amount of time and effort when compared to other options.

I designed, implemented, documented, and have continuously improved and supported DSSR. As a result, DSSR users may expect a rapid and concrete answer to their questions. My track record throughout the years has unambiguously demonstrated my dedication to DSSR. I strive to ensure that paying users' trust in DSSR is well-founded by providing them with the best services possible.

As a general rule, the CTV does not provide an evaluation license of DSSR. Potential users should watch the DSSR overview video (20m), browse the Forum, and read DSSR-related papers. If they still have questions or want to see a live demo, I would be pleased to accommodate them. Although more DSSR licenses are definitely beneficial, I do not have the time or desire to directly promote the product, including sending bulk emails to registered users of the Forum. As the developer, I can only strive to make DSSR the best it can be and let the rest sort itself out. I am a strong believer of the old Chinese saying: "酒香不怕巷子深" (Good wine needs no bush).

3DNA is obsolete and no longer maintained or supported. Thanks to the revenue from DSSR licenses, however, the following web-based resources remain accessible to the general public:
Additionally, the 3DNA Forum will be maintained so that people can assist one another and archived content would remain accessible. I may chime in occasionally, but I will not be able to continue serving the community for free as I did over the past decade.

As mentioned in my previous response, DSSR Pro has options to handle such cases, among other features.

DSSR Pro's default output reports 146 nucleotides, along with a diagnostic note for the two deformed bases. Such deformed bases can participate in a variety of loops but not in pairing interactions.

Processing file '6nd42.pdb'
  2.G.248 0.808 -- distorted, without fitted base frame
  2.G.323 0.319 -- distorted, without fitted base frame
    total number of nucleotides: 146

DSSR Pro also has an option that treats those distorted bases as normal for base-pairing interactions.

DSSR is behaving as designed. Please see the section "Identification of nucleotides" of  the 2015 DSSR paper:

A nucleotide is identified if a residue contains at least three base ring atoms and the root-mean-square deviation (rmsd) of the fit falls below a user-definable cutoff. Since base rings are rigid, the rmsd is normally <0.1 Å. To account for experimental error and special non-planar cases, such as 5,6-dihydrouridine (H2U) in yeast tRNAPhe (Figure 2), the default rmsd cutoff is set to 0.28 Å.

The default DSSR cutoff values are based on extensive tests in real-world applications. Any unidentified nucleotide is almost always due to heavy distortions in its base geometry that is 'beyond recognition'. For example, G248 in your attached 6nd42.pdb file has the PyMOL rendered image as attached. Note the N1-C2 distance is 2.2 Å, far larger than ~1.5 Å (the normal covalent C-N bond length).

DSSR Pro has provisions to handle extreme cases like yours.

RNA structures (DSSR) / Re: DSSR output
« on: October 07, 2021, 09:47:56 am »
Which version of DSSR are you using?

Hi Ying,

Given the information you provided, I can only conclude that there must be some oddity in your structure at the places where 3DNA is unable to detect the base pairs. I cannot provide any further advice before seeing the structure (or the relevant section of it).


Please provide a concrete example.

RNA structures (DSSR) / Re: How to get DSSR up and running?
« on: September 15, 2021, 11:56:26 am »
Hi Ying,

I am sorry that I forgot to update you on the progress.
Yes. I have downloaded the DSSR basic.

It is beneficial to update each topic you began so that other readers have a complete knowledge of what has occurred.

After I downloaded the DSSR software, I decompressed it and there are two files (DSSR manual and x3dna-dssr.exec) without further installation. I tried both computers, attached please find two images after I opened the .exec file. It seems that the software did not work. Is there anything wrong?

DSSR was designed with simplicity in mind. There are just two files distributed: a self-contained binary executable [x3dna-dssr (macOS and Linux) or x3dna-dssr.exe for Windows] as well as the associated PDF user manual. Because DSSR is a command-line software, it must be executed from a terminal window.

From the screenshot you attached, you are on macOS and DSSR is running as expected. Presumably, you've double-click x3dna-dssr to run it, as shown below:
x3dna-dssr ; exit;

So DSSR simply prints some help message and then exit. You must have a basic understanding of how to execute command line programs on macOS to run DSSR.

missing required option: must specify -i=PDBFile/mmCIF

type: 'x3dna-dssr -h (or --help)' for further help
      'x3dna-dssr --citation' for preferred citation(s)

Time used: 00:00:00:00

[Process completed]

Next, let me explain why I want to download the software DSSR. I used the 3DNA web sever before, but there are several base pairs missing, which may result in the incorrect calculation for the width of the major and minor groove of our RNA structure. I searched the forum and found that it may be due to the default setting for the website.  So I want to download the software and reset the parameters to see whether it can recognize the base pairs and measure the width again.

3DNA v2.4 is open source and is available to academic users after registering on the 3DNA Forum. If you have any particular queries about 3DNA v2.x, please submit them in the "General discussions (Q&As)" or "w3DNA — web interface to 3DNA" section.

In addition, I tried the DSSR web server, it failed because there was an error: Data too long for column 'jobid' at row 1. I also tried to analyze one published RNA structure (4j50)

Web DSSR ( is an unpublished work, therefore bugs are to be expected. However, it generally behaves as designed. I've just tried PDB entry 4j50 without a problem.

Please remember to include specifics so that others can REPRODUCE reported problems.

I found that there is no information about the groove width of the helix from DSSR web. So I wonder if the information will be provided by DSSR basic version?

DSSR Basic does not include some features of 3DNA v2.4; DSSR Pro does. As noted on the post "Clarification on DSSR licensing",  "DSSR Basic includes features described in the three DSSR papers (2015 DSSR, 2017 DSSR-Jmol, and 2020 DSSR-PyMOL, all published in NAR) so that reported results can be reproduced."

Users are encouraged to post any 3DNA/DSSR-related queries on the Forum. Please keep in mind to be detailed and to offer follow-up on each thread.

Best regards,


RNA structures (DSSR) / Re: Where to download the DSSR basic version
« on: September 13, 2021, 10:16:10 am »
Hi Ying,

Thanks for your follow up. DSSR-related issues are always welcome.

I can see your registration for a DSSR Basic license, as given by the CTV, as of this writing. It is now Monday morning (New York time), which may explain the delay you are experiencing. DSSR licenses are often processed quickly by the CTV support staff. Please keep us informed on your progress. If you haven't heard back from CTV by the end of the day, I'll contact them about your situation.

Best regards,


RNA structures (DSSR) / Re: Where to download the DSSR basic version
« on: September 10, 2021, 11:18:59 pm »
Hi Ying,

DSSR may only be downloaded from the Columbia Technology Venture (CTV) website. I've included a link to the CTV website in several places on this 3DNA Forum. I'm surprised that users like you are still having trouble locating where to get DSSR.

To clarify, I changed the header link "DSSR License" to "DSSR Download/Licensing". The DSSR download link is also included in my signature at the bottom of each of my posts. See also the post "Clarification on DSSR licensing".

Registration on the 3DNA Forum is required in order to obtain the classic 3DNA v2.4 (and SCHNAaP/SCHNArP), and ask 3DNA/DSSR-related questions.

Please let me know if there is anything else I can do to make this message crystal clear.

Best regards,


As a followup, DSSR Pro now has the option to derive only pairs across chains.

DSSR Basic does not have the base mutations feature at all. Also note that DSSR Basic is provided AS IS without any warranty of support.

That said, DSSR Basic does include features described in the three DSSR papers (2015 DSSR, 2017 DSSR-Jmol, and 2020 DSSR-PyMOL, all published in NAR) so that reported results can be reproduced. The DSSR Basic manual should function as expected. Anything to the contrary will be considered a bug and will be fixed as soon as possible.

DSSR Pro includes new advanced features, plus all functionality of 3DNA v2.4, as well as full support. Please watch the DSSR Overview Video.

Instead of DSSR/3DNA v2.4, you may want to try other software tools such as RNAView, FR3D, MC-Annotate, or Curves+ etc. Please let us know what you find.

Best regards,


Through another attempt, I found a solution to the problem.

Please elaborate on what you did that resulted in a solution to the problem.



General discussions (Q&As) / Re: 3DNA manual
« on: July 28, 2021, 09:16:09 am »
Check the $X3DNA/doc folder.

Remember to post specific questions in a new thread with a clear subject line.

Reading posts linked at "Netiquette" at the upper-left corner of the Forum should help.

Best regards,


Hi chen long,

1. After I got the academic license through Columbia University, I downloaded two versions of dssr-basic for linux and windows. But the windows version of the exe installation package can't open all the time. I have tried it on several computers with win7 and win10, but it doesn't work, so I would like to ask Dr. Lu why.

This is the first time I've heard of problems installing DSSR on Windows and Linux.

I do not understand what you mean by "But the windows version of the exe installation package can't open all the time." Does it work sometime? If so, when and under what condition? What do you mean by "it doesn't work"? Please provide screenshots to illustrate unambiguously the issues you experienced.

2. The files in the linux installation package are not in tar.gz format. I don't know how to install it. Could you please tell me. Or is there an installation method I haven't found? I did find it for a long time.

Then what format do you have from CTV download set? How long have you tried to find any other installation format?

It is fashionable these days to discuss the reproducibility of scientific publications. It's also crucial to ask questions in a consistent manner.

Best regards,


DSSR Pro can do it and more.


RNA structures (DSSR) / Re: how to repair a DNA model
« on: July 27, 2021, 11:48:48 am »
Please provide some background info and a concrete example to illustrate unambiguously what you want to achieve.



Yes, I tried and finally manage to color differently at each nucleotide blocks.

Glad to know that you have managed to color nucleotide blocks as desired. This is an important first step for later on speed optimizations.

But it is quite slow since it make all individual block object for every nucleotide.

How many colors do you want to have? Grouping nucleotides with the same color should speed up the process. It is now a matter of PyMOL selection syntax to play with.

And also it print lots of warning messages during the run.
I can't locate the origin of this warning.
PyMOL>dssr_block (chain J and resi 56), block_color='N:[1.0 0.393 0.0]'

I cannot reproduce the warning messages. Let's not worry about them right now.

Best regards,


Bug reports / Re: Uncaught exception error
« on: July 21, 2021, 09:50:10 pm »

The DSSR version you used is v1.9.4-2019jul08. The latest DSSR version is v2.3.2-2021jun29, which works as expected for PDB entry 6jwe, as shown below:

Code: [Select]
x3dna-dssr --more --loop=with-stems --json -i=6jwe.pdb -o=6jwe.json

Processing file '6jwe.pdb'
    total number of nucleotides: 20
    total number of base pairs: 18
    total number of helices: 2
    total number of multiplets: 4
    total number of atom-base capping interactions: 2
    total number of splayed-apart dinucleotides: 2
    total number of non-loop single-stranded segments: 1
    total number of G-tetrads: 3
    total number of G4-helices: 1
    total number of G4-stems: 1

So please update your DSSR to the latest version (available exclusively from Columbia Technology Ventures).

Best regards,


RNA structures (DSSR) / Re: Classical RNA loop motifs
« on: July 19, 2021, 08:49:19 am »
Hi Dr. Baulin,

As I understand correctly, for the moment there is no program (or database) that annotates (or stores) classical RNA loop motifs explicitly.
By the classical RNA loop motifs I mean sarcin/ricin loop, E-loop, tandem sheared G-A, GA/AAG internal loop, UAA/GAN internal loop, kink-turn, etc.

You may be right. Your list of 'classical RNA loop motifs' includes `etc.` and I am not sure/aware of the complete list.

As I know it:
1) only kink-turns are annotated by DSSR.

DSSR isn't intended to be a comprehensive tool for annotating 'classical RNA loop motifs.' DSSR, on the other hand, includes the fundamentals (such as base-pairing/stacking annotations and backbone torsions) that should make any downstream pipeline easier to annotate any well-defined RNA structural motifs.

DSSR can auto-detect kink-turns because K-turns have striking structural features and important functional roles, and I want to have a thorough understanding of the motif. Personally, I've found that only by implementing a topic/concept in detail source code can I truly comprehend it.

The Tamar Schlick made use of this DSSR features in their 2017 NAR paper "Using sequence signatures and kink-turn motifs in knowledge-based statistical potentials for RNA structure prediction." Please take a look at the following two threads (which also demonstrate the value of the 3DNA Forum) initiated by lead author of the paper:

2) for sarcin/ricin loop, E-loop, and tandem sheared G-A the best way of annotation is to use manually curated annotation from RNAMotifContrast and merge it with the RNA Motif Atlas clusters' identifiers.

RNAMotifContrast and RNA Motif Atlas clusters are certainly well-known resources on the topic. Another source of information that is worth checking is the Janusz Bujnicki lab website.

3) for GA/AAG internal loop and UAA/GAN internal loop annotation there are no existing ways at all.

DSSR has a dedicated section of ALL internal loops. Filtered by sequence constraints and geometric constraints, you might find what you're looking for.

If I'm wrong, could you please let me know if I missed anything?
If I'm right, are there any plans to add the mentioned motifs to DSSR functionality in the future?

In the future, I may add more motif annotations to DSSR Pro.

Best regards,


In principle, I understand what you're trying to accomplish. However, I am unable to provide any concrete answers due to a lack of information.

Please pay close attention to my requests for clarification.

Code: [Select]
X.g1 - Z.C112;
X.G2 - Z.U111;
X.G41 - Z.A63;
X.G41 - Z.C82;
X.U42 - Z.A81;
X.U42 - Z.C82;

Are you sure this is the dot-bracket notation, with desired base-pairs you want???

What the .dbn should be in this case (2YIE, between chains X and Z)?

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