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Welcome > Feature requests
Internal loops
cigdem:
Hi Xiang-Jun,
I need to gather some information on internal loops and I believe DSSR would be a great tool for this purpose.
What I need is for example for 1E7K:
1) Length of the unpaired regions as you give in internal loops section:
****************************************************************************
List of 2 internal loops
1 asymmetric internal loop: nts=11; [5,2]; linked by [#1,#2]
nts=11 CAAUGAGCGAG C.C28,C.A29,C.A30,C.U31,C.G32,C.A33,C.G34,C.C42,C.G43,C.A44,C.G45
nts=5 AAUGA C.A29,C.A30,C.U31,C.G32,C.A33
nts=2 GA C.G43,C.A44
2) Nucleotide numbers of first and last pairs of the helices as you give in the kink turns section (but I need this info for non kink-turns, too):
****************************************************************************
List of 2 possible kink turns
1 Normal k-turn with GA on helix#1 (same as C- and NC-helix); iloop#1
C#1[CG C.C28,C.G45] [GA C.G32,C.A44] NC#2[CG C.C42,C.G34]
strand1 nts=10; GCCAAUGAGG C.G26,C.C27,C.C28,C.A29,C.A30,C.U31,C.G32,C.A33,C.G34,C.G35
strand2 nts=7; CCGAGGC C.C41,C.C42,C.G43,C.A44,C.G45,C.G46,C.C47
3) Length of the helices as you give in the stems section:
****************************************************************************
List of 4 stems
Note: a stem is defined as a helix consisting of only canonical WC/wobble
pairs, with a continuous backbone.
stem#number[#helix-number containing this stem]
Other terms are defined as in the above Helix section.
--------------------------------------------------------------------
stem#1[#1] bps=3
strand-1 5'-GCC-3'
bp-type |||
strand-2 3'-CGG-5'
helix-form AA
1 C.G26 C.C47 G-C WC 19-XIX cWW cW-W
2 C.C27 C.G46 C-G WC 19-XIX cWW cW-W
3 C.C28 C.G45 C-G WC 19-XIX cWW cW-W
--------------------------------------------------------------------------
stem#2[#1] bps=2
strand-1 5'-GG-3'
bp-type ||
strand-2 3'-CC-5'
helix-form .
1 C.G34 C.C42 G-C WC 19-XIX cWW cW-W
2 C.G35 C.C41 G-C WC 19-XIX cWW cW-W
--------------------------------------------------------------------------
So, for 1E7K the information would be like:
1E7K C 5 2 28 45 42 34 3 2
I need this information also for other internal loops that don't have a kink-turn. Do you think it is applicable?
Thanks a lot.
Cigdem Bayrak
xiangjun:
Hi Cigdem,
Thanks for your request. It makes sense to add a new field (maybe termed "summary") that collects the info you need for each DSSR-identified loop. I'll look into the issue and report back when the requested feature is implemented (presumably within this week).
Best regards,
Xiang-Jun
cigdem:
Hi Xiang-Jun,
That is great! Thanks a lot.
Sincerely,
Cigdem Bayrak
xiangjun:
Hi Cigdem,
I've added a new field, termed "summary", to all DSSR-derived loops. Now the results (using 1e7k as an example) are as below:
# x3dna-dssr -i=1e7k.pdb
1 asymmetric internal loop: nts=11; [5,2]; linked by [#1,#2]
summary: [2] 5 2 [C.28 C.45 C.34 C.42] 3 2
nts=11 CAAUGAGCGAG C.C28,C.A29,C.A30,C.U31,C.G32,C.A33,C.G34,C.C42,C.G43,C.A44,C.G45
nts=5 AAUGA C.A29,C.A30,C.U31,C.G32,C.A33
nts=2 GA C.G43,C.A44
2 asymmetric internal loop: nts=11; [5,2]; linked by [#3,#4]
summary: [2] 5 2 [D.28 D.45 D.34 D.42] 3 2
nts=11 CAAUGAGCGAG D.C28,D.A29,D.A30,D.U31,D.G32,D.A33,D.G34,D.C42,D.G43,D.A44,D.G45
nts=5 AAUGA D.A29,D.A30,D.U31,D.G32,D.A33
nts=2 GA D.G43,D.A44
Note that I've put the number of stems in the first set of [] and closing (canonical) pairs in the second set of [] to make the different sections more distinct. The pairs are designated with chain-id.residue-number to avoid ambiguity (for the most common cases).
While I could introduce an option to output exactly what your described, please consider the above output format for your application. Download DSSR again, and let me know if that fits your bill.
Xiang-Jun
PS:
* Regarding RNA loop motifs, do not forget the impressive work already done by the Leontis-Zirbel lab.
* For k-turn motifs, see also the authoritative work from the David Lilley group (specifically, their computer program in Python 2.7 for identifying k-turns).
cigdem:
Hi Xiang-Jun,
This is exactly what I needed! Thank you so much for making things so easier.
Just one more thing, if it is applicable could you please also add kink-turn information at the end of the summary line? So that if the corresponding internal loop has a kink-turn, it will say "kt" maybe?
Thank you again.
Best regards,
Cigdem
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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.
