Multi-chain/multi-template Modeling
Hey there Modellers,
I appreciate the input I received from my previous questions, but have run into something I need more clarification on. I'm attempting to product models using multiple templates and multiple chains. I'll detail my steps below:
Step 1: Build individual chain profiles using build_profile.py, as seen in the basic tutorial (select PDBs based on e-val and identity thresholds).
Step 2: Use the multiple template salign.py program as seen in the advanced tutorial (the first script in the tutorial), on PDBs selected in step 1.
Step 3: Here I attempted to combine alignment profiles. I wrote a quick python script to do so. I'll show a snippet of the output below, please note that some structures only offer one chain that could be used as a template, if this was the case I use a hyphen a placeholder... which I think is the source of at least one of my problems.
>P1;2bnu structure:2bnu: 1 :A:252 :B:::-1.00:-1.00 --QEVTQIPAALSVPEGENLVLNCSFTDSAIYNLQWFRQDPGKGLTSLLLIQSSQREQTSGRLNASLDKSSGRST LYIAASQPGDSATYLCAVRPTSGGSYIPTFGRGTSLIVHPYIQNPDPAVYQLRRSKSSDKSVCLFTDFDSQTNVS QSKD--SDVYITDKCVLDMRSMDFKSNSAVAWSNKSDFACANAFNNSIIPEDTFFPS-----/ --GVTQTPKFQVLKTGQSMTLQCAQDMNHEYMSWYRQDPGMGLRLIHYSVGAGITDQGEVPNGYNVSRSTTEDFP LRLLSAAPSQTSVYFCASSYVG-N-TGELFFGEGSRLTVLEDLKNVFPPEVAVFEPSEAEISHTQKATLVCLATG FYPDHVELSWWVNGKEVHSGVCTDPQPLKEQPALNDSRYALSSRLRVSATFWQDPRNHFRCQVQFYGLSENDEWT QDRAKPVTQIVSAEAWGRAD-------*
>P1;5bs0 structure:5bs0: 1 :D:252 :E:::-1.00:-1.00 -AQEVTQIPAALSVPEGENLVLNCSFTDSAIYNLQWFRQDPGKGLTSLLYVRPYQREQTSGRLNASLDKSSGRST LYIAASQPGDSATYLCAVRPGGAGPFFVVFGKGTKLSVIPNIQNPDPAVYQLRDSKSSDKSVCLFTDFDSQTNVS QSKD--SDVYITDKCVLDMRSMDFKSNSAVAWSNKSDFACANAFNNSIIP------------/ ---------------------------------------------------------------------------
---------------------------------------------------------------------------
---------------------------------------------------------------------------
---------------------------*
>P1;4grm structure:4grm: 1 :A:252 :B:::-1.00:-1.00 --------------------------------------------------------------------------
--------------------------------------------------------------------------
--------------------------------------------------------------/ --GVTQTPKFQVLKTGQSMTLQCAQDMNHEYMSWYRQDPGMGLRLIHYSVGAGITDQGEVPNGYNVSRSTTEDFP LRLLSAAPSQTSVYFCASRPGL---QPEQYFGPGTRLTVTEDLKNVFPPEVAVFEPSEAEISHTQKATLVCLATG FYPDHVELSWWVNGKEVHSGVCTDPQPLKEQPALNDSRYALSSRLRVSATFWQDPRNHFRCQVQFYGLSENDEWT QDRAKPVTQIVSAEAWGRAD-------*
>P1;2pye sequence:2pye: 1 :A:252 :B:::-1.00:-1.00 MKQEVTQIPAALSVPEGENLVLNCSFTDSAIYNLQWFRQDPGKGLTSLLLIQSSQREQTSGRLNASLDKSSGSST LYIAASQPGDSATYLCAVRPLLDGTYIPTFGRGTSLIVHPYIQNPDPAVYQLRDSKSSDKSVCLFTDFDSQTNVS QSKDSDVYITDKCVLDMRSMDFKSNSAVAWSNKSDFACANAFNNS/ MGVTQTPKFQVLKTGQSMTLQCAQDMNHEYMSWYRQDPGMGLRLIHYSVGAGTTDQGEVPNGYNVSRSTIEDFPL RLLSAAPSQTSVYFCASSYLGNTGELFFGEGSRLTVLEDLKNVFPPEVAVFEPSEAEISHTQKATLVCLATGFYP DHVELSWWVNGKEVHSGVCTDPQPLKEQPALNDSRYALSSRLRVSATFWQDPRNHFRCQVQFYGLSENDEWTQDR
AKPVTQIVSAEAWGRAD*
Step 4:
Next, I attempted to use the second salign.py script in the advanced tutorial, hoping for PDB-multi.ali and PDB-multi.prf files which I did not receive. The error code was as seen below:
_modeller.ModellerError: rdpdb___303E> No atoms were read from the specified input PDB file, since the starting residue number and/or chain id in MODEL_SEGMENT
(or the alignment file header) was not found; requested starting position: residue number " 1", chain " A"; atom file name: 2bnu.pdb
I'm assuming this has to do with the pdbID_fit.pdb files outputted by the program in step 2. So am I merging my alignment file too late? I'm also assuming the pdbID_fit.pdb file must contain both chains. Regardless any guidance for producing models from this would be very useful.
Best,
Ryan
On 9/8/17 1:17 PM, Ryan Ehrlich wrote: > I appreciate the input I received from my previous questions, but have > run into something I need more clarification on. I'm attempting to > product models using multiple templates and multiple chains. I'll detail > my steps below:
Your steps look fine to me, including the use of gaps for the single-chain structures. But your 2pye template doesn't look right to me - normally you'd want all the chain breaks to line up, but it looks like your A chain finishes about 15 residues earlier than in the other templates. You probably want to pad this out with gap characters (-) as right now part of your 2pyeB chain is aligned with the A chain of the other templates.
> _modeller.ModellerError: rdpdb___303E> No atoms were read from the > specified input PDB file, since the starting residue number and/or chain > id in MODEL_SEGMENT > (or the alignment file header) was not found; requested starting > position: residue number " 1", chain " A"; atom file name: 2bnu.pdb
This seems pretty self-explanatory, no? In your alignment file you ask Modeller to read ATOM records from 2bnu.pdb, starting at residue 1 in chain A and ending at residue 252 in chain B. But there isn't an ATOM record for residue 1 (it starts at residue 2). (There also isn't a residue 252 in chain B.)
Ben Webb, Modeller Caretaker
participants (2)
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Modeller Caretaker
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Ryan Ehrlich