Cover images 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.
Details on how to reproduce the cover images are available on the 3DNA Forum.
Structure of the human minor spliceosome pre-B complex (PDB id: 8Y7E; Bai R, Yuan M, Zhang P, Luo T, Shi Y, Wan R. 2024. Structural basis of U12-type intron engagement by the fully assembled human minor spliceosome. Science 383: 1245–1252). The protein–RNA assembly reveals the mechanisms of recognition and recruitment of several small nuclear ribonucleoproteins (snRNPs) involved in the splicing of U12-type introns. The pre-mRNA is depicted by a red ribbon, and the U12 small nuclear RNA (snRNA) by a green 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; the proteins are shown as 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).
Human tRNA splicing endonuclease (TSEN) complex bound to pre-tRNAArg (PDB id: 7UXA; Hayne CK, Butay KJ, Stewart ZD, Krahn JM, Perera L, Williams JG, Petrovitch RM, Deterding LJ, Matera AG, Borgnia MJ, Stanley RE. 2023. Structural basis for pre-tRNA recognition and processing by the human tRNA splicing endonuclease complex. Nat Struct Mol Biol 30: 824–833). Cryo-EM structure of the TSEN protein assembly with pre-tRNAArg provides insights into the recognition and splicing of an intron that must be removed from the pre-tRNA before translation. The pre-tRNAArg 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; the TSEN subunits are shown as 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).
Systemic RNA interference defective protein 1 (SID1) in complex with dsRNA (PDB id: 8XC1; Wang R, Cong Y, Qian D, Yan C, Gong D. 2024. Structural basis for double-stranded RNA recognition by SID1. Nucleic Acids Res 52: 6718–6727). The cryo-EM structure provides a major step towards understanding the mechanism of dsRNA recognition by SID1, involving extensive interactions between basic amino-acid residues and the sugar-phosphate backbone. The dsRNA chains are depicted by red, green, blue, and yellow ribbons, with bases and Watson-Crick base pairs represented as color-coded blocks and minor-groove edges colored white: A/A-U in red, C/C-G in yellow, G/G-C in green, U/U-A in cyan; SID1 is shown 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).
Complex of arginyl-tRNA-protein transferase 1 (ATE1) with tRNAArg and a short peptide substrate (PDB id: 8UAU; Lan X, Huang W, Kim SB, Fu D, Abeywansha T, Lou J, Balamurugan U, Kwon YT, Ji CH, Taylor DJ, Zhang Y. 2024. Oligomerization and a distinct tRNA-binding loop are important regulators of human arginyl-transferase function. Nat Commun 15: 6350). The ATE1 homodimer dissociates upon binding the peptide and forms a loop that wraps around tRNAArg. The tRNAArg 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; ATE1 is shown by a gold ribbon and the peptide 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).
Structure of endoribonuclease P (RNase P) in complex with pre-tRNAHis-Ser (PDB id: 8CBK; Meynier V, Hardwick SW, Catala M, Roske JJ, Oerum S, Chirgadze DY, Barraud P, Yue WW, Luisi BF, Tisné C. 2024. Structural basis for human mitochondrial tRNA maturation. Nat Commun 15: 4683). The structure reveals the first step of human mitochondrial tRNA maturation by RNase P, processing the 5′-leader of pre-tRNA. The RNA 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; the protein assembly is shown by the 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).
Structure of a group II intron ribonucleoprotein in the pre-ligation state (PDB id: 8T2R; Xu L, Liu T, Chung K, Pyle AM. 2023. Structural insights into intron catalysis and dynamics during splicing. Nature 624: 682–688). The pre-ligation complex of the Agathobacter rectalis group II intron reverse transcriptase/maturase with intron and 5′-exon RNAs makes it possible to construct a picture of the splicing active site. The intron is depicted by a green 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; the 5′-exon is shown by white spheres 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).
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).
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).
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).
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).
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).
From early on, 3DNA calculates the Zp parameter to separate A- and B-DNA double helical steps. First introduced in the paper A-form conformational motifs in ligand-bound DNA structures (see figure below), Zp is the mean projection of the two phosphorus atoms onto the z-axis of the dimer ‘middle frame’. Zp is greater than 1.5 Å for A-DNA, and it is less than 0.5 Å for B-DNA. As noted in the 3DNA NAR paper, other parameters such as slide should also be examined to confirm conformational assignments based on Zp.
As of v2.1, 3DNA has introduced the single-stranded variant for the Zp parameter (ssZp) as a more robust substitute for the Richardson phosphorus-glycosidic bond distance parameter (Dp) to characterize sugar puckers. See post Sugar pucker correlates with phosphorus-base distance for more details. In 3DNA/DSSR, ssZp is defined as the z-coordinate of the 3′ phosphorus atom expressed in the standard reference frame of the preceding base; it is positive when phosphorus lies on the +z-axis side (base in anti conformation) and negative if phosphorus is on the –z-axis side (base in syn conformation). Note that by definition, Dp should always be positive.
As in the previous post, here I am using G175 and U176 of PDB entry 1jj2 (the large ribosomal subunit of Haloarcula marismortui) as examples to illustrate how the ssZp parameters are calculated. The GpU forms a dinucleotide platform, where the sugar of G175 adopts a C2′-endo conformation, and that of U176 C3′-endo. For verification, here is the PDB data file for fragment 1jj2-G175-U176-A177.pdb (note A177 is included for its phosphorus atom). Run the following 3DNA commands:
find_pair -s 1jj2-G175-U176-A177.pdb stdout
frame_mol -1 ref_frames.dat 1jj2-G175-U176-A177.pdb ref-G175.pdb
frame_mol -2 ref_frames.dat 1jj2-G175-U176-A177.pdb ref-U176.pdb
File ref-G175.pdb contains the following line:
ATOM 24 P U 0 176 -5.624 6.937 1.918 1.00 24.19 P
The z-coordinate of U176 (which is 3′ to G175) is 1.918, which is the ssZp for G175. It is less than 2.9 Å, corresponding to the C2′-endo sugar conformation of G175.
Similarly, file ref-U176.pdb contains the following line:
ATOM 44 P A 0 177 -3.841 6.592 4.377 1.00 25.91 P
So the ssZp for U176 is 4.377, which is greater than 2.9 Å, corresponding to the C3′-endo sugar conformation of U176.
To sum up, the double-stranded Zp as originally available from 3DNA can be used for discriminating A- and B-DNA double-helical steps: Zp > 1.5 Å for A-DNA, and Zp < 0.5 Å for B-DNA. The newly introduced single-stranded Zp is intended for characterizing sugar puckers: Zp > 2.9 Å for C3′-endo, and Zp < 2.9 Å for C2′-endo. Since A-DNA has predominately C3′-endo sugar conformation and B-DNA has C2′-endo sugar, the ssZp parameter would be helpful in classifying a dinucleotide into A- or B-like conformation. A survey of ssZp in well-defined A- and B-DNA structures (as performed for double-stranded Zp) should prove useful.
Realizing the naming confusions of double-stranded Zp vs single-stranded Zp, I am considering to rename single-stranded Zp as ssZp in future releases of 3DNA and DSSR. Do you have any comments or suggestions? Please let me know by leaving a comment!
Recently I was surprised by some cases of nucleotides with missing atoms in PDB entry 1pns. The story started like this: 3DNA/DSSR maps various nucleotide names to one-letter codes, based on the data file baselist.dat (see post Modified nucleotides in the PDB). In the meantime, 3DNA/DSSR internally assigns a nucleotide as either purine or pyrimidine, by virtue of coordinates of base atoms. Be definition, purines should only include A/a/G/g/I/i, and pyrimidines C/c/T/t/U/u/P/p. However, no consistency check has been implemented in DSSR until just now.
I first noticed the inconsistency between residue name and atom coordinates for nucleotide A6 on chain U (hereafter referred to as U.A6) in 1pns. The nucleotide has standard name ‘ A’, obviously a purine. However, somehow DSSR classified it as a pyrimidine based on atomic coordinates. Upon further check of the PDB data file, I found the following remarks:
REMARK 470 MISSING ATOM
REMARK 470 THE FOLLOWING RESIDUES HAVE MISSING ATOMS(M=MODEL NUMBER;
REMARK 470 RES=RESIDUE NAME; C=CHAIN IDENTIFIER; SSEQ=SEQUENCE NUMBER;
REMARK 470 I=INSERTION CODE):
REMARK 470 M RES CSSEQI ATOMS
REMARK 470 A U 6 N9 C8 N7
REMARK 470 G U 8 N9 C8 N7
REMARK 470 A U 12 N9 C8 N7
REMARK 470 A U 13 N9 C8 N7
REMARK 470 A U 14 N9 C8 N7
The atomic coordinates for U.A6 are as below:
ATOM 34447 P A U 6 81.861 37.210 78.651 1.00378.87 P
ATOM 34448 OP1 A U 6 80.631 37.121 77.831 1.00378.87 O
ATOM 34449 OP2 A U 6 81.665 37.221 80.119 1.00378.87 O
ATOM 34450 O5' A U 6 82.707 38.495 78.212 1.00378.87 O
ATOM 34451 C5' A U 6 83.948 38.777 78.887 1.00378.87 C
ATOM 34452 C4' A U 6 84.600 40.000 78.276 1.00378.87 C
ATOM 34453 O4' A U 6 84.975 39.698 76.901 1.00378.87 O
ATOM 34454 C3' A U 6 83.714 41.239 78.153 1.00378.87 C
ATOM 34455 O3' A U 6 83.654 41.968 79.369 1.00378.87 O
ATOM 34456 C2' A U 6 84.403 42.015 77.020 1.00378.87 C
ATOM 34457 O2' A U 6 85.564 42.655 77.474 1.00378.87 O
ATOM 34458 C1' A U 6 84.834 40.864 76.105 1.00378.87 C
ATOM 34459 C5 A U 6 82.033 39.296 74.209 1.00378.87 C
ATOM 34460 C6 A U 6 82.941 39.553 75.166 1.00378.87 C
ATOM 34461 N6 A U 6 81.170 39.949 72.090 1.00378.87 N
ATOM 34462 N1 A U 6 83.830 40.588 75.041 1.00378.87 N
ATOM 34463 C2 A U 6 83.843 41.410 73.939 1.00378.87 C
ATOM 34464 N3 A U 6 82.899 41.124 72.974 1.00378.87 N
ATOM 34465 C4 A U 6 81.968 40.108 73.016 1.00378.87 C
No atom records for N7, C8 and N9. So far, so good. However, surprise came when I visualized U.A6 in Jmol, as shown in the following image. Note here atom N1 is connected to C1’ as in pyrimidines, and N6 is bonded to C4!
The same issue also exists for U.G8 (see figure below), U.A12, U.A13, and U.A14.
It is beyond my imagination to understand why such weird cases exist in the PDB, even given the lousy resolution (8.7 Å) of 1pns.
I recently upgraded my Macs to OS X Mavericks to check if 3DNA/DSSR works in the new operating system. I am glad to report that both run without a hitch, as expected.
Since OS X Mavericks is free from the Mac App Store, it will quickly become the de facto version virtually all Mac users would use. I also noticed that Ruby on Mavericks has been upgraded to ruby 2.0.0p247 (2013-06-27 revision 41674), a major step forward from the now retiring Ruby 1.8.7 distributed in previous versions of Mac OS X.
As a rule, I’d ensure that 3DNA/DSSR executes properly in major releases of the commonly used operating systems — Mac, Windows, and Linux.
While having not used DOS for ages, I am glad to find that the DSSR version compiled for MinGW/MSYS on Windows works perfectly under this operating system (see screenshot below). The DSSR DOS command-line interface functions exactly the same as for Linux, Mac OS X, MinGW/MSYS, and CygWin. Among other possible usages, it allows for batch files to take advantage of DSSR.
Implementing DSSR in strict ANSI C as a self-contained and zero-dependent command-line program pays off enormously: it simplifies code maintenance and ensures that the program is applicable wherever a C compiler exists. The easy web interface to DSSR makes the program universally accessible.
Aside from its extensive functionality for RNA structural analyses, DSSR also introduces a consistent and flexible way to process command-line options. Here, each option can be specified via a --key[=value] pair (or -key[=value] or key[=value]; i.e., two/one/zero preceding dashes are all accepted), key can be in either lower, UPPER or MiXed case, and value is optional for Boolean switches. Furthermore, options can be put in any order; if the same key is repeated more than once, the value specified last overwrites corresponding previous settings.
As always, the rules are best illustrated with concrete examples. Some typical use-cases are given below:
#1 analyze PDB entry '1msy', with default output to stdout
x3dna-dssr --input=1msy.pdb
#2 same as #1, with output directed to file '1msy.out'
x3dna-dssr --input=1msy.pdb --output=1msy.out
#3-6, same as #2
x3dna-dssr --output=1msy.out --input=1msy.pdb
x3dna-dssr --OUTPUT=1msy.out --Input=1msy.pdb
x3dna-dssr -output=1msy.out input=1msy.pdb
x3dna-dssr output=1msy.out --input=1msy.pdb
#7 the value '1ehz.pdb' overwrites '1msy.pdb'
x3dna-dssr --input=1msy.pdb input=1ehz.pdb
#8-12 with the switch --more set to true
x3dna-dssr -input=1msy.pdb --more
x3dna-dssr -input=1msy.pdb --more=true
x3dna-dssr -input=1msy.pdb --more=yes
x3dna-dssr -input=1msy.pdb --more=on
x3dna-dssr -input=1msy.pdb --more=1
#13 same as without specifying --more,
# or with values set to false/no/0
x3dna-dssr -input=1msy.pdb --more=off
#14 shorthand forms for --input and --output
x3dna-dssr -i=1msy.pdb -o=1msy.out
#15 it can also be more verbose
x3dna-dssr --input-pdb-file=1msy.pdb
#16-18 within a key, separator dash(-) and underscore (_)
# are treated the same, and can be omitted
x3dna-dssr -i=1msy.pdb -non-pair
x3dna-dssr -i=1msy.pdb -non_pair
x3dna-dssr -i=1msy.pdb -nonpair
By allowing for 2/1/0 dashes to precede each key and a dash/underscore character or none to separate words within the key, DSSR provides users with great flexibility in specifying command-line options to fit into their preferred styles. Not surprisingly, new programs to be added into 3DNA, or the version 3 release of the software will all follow the same convention.
In addition to the five canonical bases (A, C, G, T, and U), nucleic acid structures in the PDB contains numerous modified variants (natural or engineered) in the nucleobase, sugar, or the phosphate. For instance, the 76-nt (nucleotide) long yeast phenylalanine tRNA (1ehz) contains 14 modified bases: 2MG10, H2U16, H2U17, M2G26, OMC32, OMG34, YYG37, PSU39, 5MC40, 7MG46, 5MC49, 5MU54, PSU55, and 1MA58. Among which, the most prevalent and best-known example is pseudouridine. Note that in the PDB, each residue (including modified nt) is named with an up to three-letter identifier, e.g., PSU for pseudouridine. For a comprehensive list (with chemical and structural information) of small molecules, including modified nts, please refer to the Ligand Expo website hosted by the RCSB PDB.
Given the widespread occurrences of modified bases in nucleic acid structures, any practical structural bioinformatics software should be able to treat them effectively, as with the canonical bases. In 3DNA, from the very beginning, modified bases are mapped to standard counterparts, e.g. 5‐iodouracil (5IU) to uracil (U) and 1‐methyladenine (1MA) to adenine (A), allowing for easy analysis of unusual DNA and RNA structures (see the NAR03 reference). Specifically, in the 3DNA distribution the file baselist.dat contains the mappings explicitly.
As of v2.1, 3DNA automatically maps a new modified base not available in the file baselist.dat. Yet, I have continuously updated the list in line with new DNA/RNA entries released by the PDB. The process is automated with a Ruby script which calls find_pair -s on each nucleic-acid-containing structure to output unknown bases. As an extreme, the baselist.dat file below comprises only canonical bases:
A A
C C
G G
T T
U U
DA A
DC C
DG G
DT T
With the above minimum mapping list, running the command find_pair -s on 1ehz.pdb identifies all the 14 modified bases. A sample case for 2MG is shown below:
Match '2MG' to 'g' for residue 2MG 10 on chain A [#10]
check it & consider to add line '2MG g' to file <baselist.dat>
By parsing the output of a batch run on all DNA/RNA-containing entries in the PDB as of October 18, 2013, I identified a total of 596 modified bases. The top portion is as below:
02I a
08Q c
08T a
0AD g
0C c
0DC c
0DG g
0DT t
0G g
0KL u
0KX c
0KZ t
An explicit list of base mapping makes the correspondence transparent, and helps avoid ambiguous cases as to which canonical base a modified nt matches to. DSSR uses the same list internally. Hopefully, the information would also be useful to other related projects.
Recently I was a bit surprised to find that the methyl group is named differently in the PDB: C7 in DT8 (thymine) of B-DNA 355d, CM5 in 5MC40 (5-methylated C) of tRNA 1ehz, and C5M in 5MU54 (5-methylated U, i.e., T) of the same tRNA 1ehz. See the three figures below for details.
I know that the previously named C5M of thymine in DNA has been renamed C7 as a result of the 2007 remediation effort (PDB v3). However, browsing through the wwPDB Remediation website and reading carefully the article Remediation of the protein data bank archive, I failed to see explanations of the obvious inconsistency of CM5 (5MC40) vs C5M (5MU54) in the nomenclature of the 5-methyl group in the same tRNA entry 1ehz, except for the following note:
As with the Chemical Component Dictionary, names for standard amino acids and nucleotides follow IUPAC recommendations (10) with the exception of the well-established convention for C-terminal atoms OXT and HXT. These nomenclature changes have been applied to standard polymeric chemical components only.
5-methyl is named C7 in DT8 of the DNA entry 355d
5-methyl is named CM5 in 5MC40 of the RNA entry 1ehz
5-methyl is named C5M in 5MU54 of the RNA entry 1ehz
Am I missing something obvious? If you have any further information, please leave a comment. Whatever the case, it helps (at least won’t hurt) to know the naming discrepancy for those who care about the small methyl group in nucleic acid structures.
Recently, I upgraded my local ViennaRNA package installation from v2.0.7 to v2.1.3 on my Mac. Following Quickstart in the INSTALL file, I ran ./configure successfully, but make aborted with error messages. Since I previously had a working copy of the software, it must be configuration issues when I compiled this new version. After a few iterations of checking the error message and reading through the INSTALL file, I came up with the following settings:
./configure --disable-openmp --without-perl
make
sudo make install
Apart from some warning messages, the above make command ran successfully.
This post serves mainly as a note for my own reference. Hopefully, the information may prove useful to others who try to install the versatile ViennaRNA package on a Mac OS X machine.
I’ve come up with a preliminary web-interface to DSSR, currently accessible at URL http://web.x3dna.org/dssr. The DSSR web-interface has been tested on Safari, Firefox, Chrome, and IE, with satisfying results. A screenshot of the home page is given below, using 1msy as an example:
After clicking the Submit button, users will be presented with the result page of a DSSR run. The beginning portion of the above example is as follows:
Note that the DSSR web-interface is being provided via a shared web hosting service, thus it has limited resources. Specifically, the uploaded file cannot be larger than two megabytes (2MB), and the process could be slow. Additionally, the file must have an extension of .pdb or .cif. To take full advantage of what DSSR has to offer, please install and run the software locally.
By design, DSSR is self-contained, command-line driven, with zero dependance on third-party libraries. Such features make it straightforward to build a GUI- or web-interface to DSSR, or integrate the program into other structural bioinformatics tools. As the need arises, I will refine the DSSR web-interface to better serve the community. The current simple, yet exploratory, web interface should make DSSR accessible to a much wider audience.
