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Re: [modeller_usage] using BLAST to find templates for modelling



Nick Fusseder wrote:
My scenario:
I am running a BLAST search against PDB sequences in order to find suitable
templates to model my target protein. I have all PDB structures locally
installed and the atom_files variable pointing to this directory in my .py
scripts.

I basically have 2 questions:

1. From what I understand the modlib/CHAINS_all.seq is used to store the
sequences for the PDB structures. Now if I want to use a novel PDB structure
as a template which is not included in this list, will I have to manually
create the chain sequence in PIR format (with commands/make_chains.py) and
append it to the modlib/CHAINS_all.seq file?
ALso is there a way to create a CHAIN_all.seq file from all PDB structure
files in one go?

CHAINS_all.seq holds the sequences from PDB (although it is not kept up to date, obviously). It's only used for searching. I don't know what made you think you need to put your own sequences in there (perhaps our documentation is misleading?).

2. Since I am already running a BLAST search to find my template structures,
I won't be using search.py. In order to create the .ali alignment file which
is neccessary for the computation of the final structure prediction of my
target sequence, i will need to run malign.py. The problem is, malign takes
a .seg file as input. I have not yet found an automated method to generate
such a .seg file from a target sequence and template structures found by
BLAST. Will I have to create the .seg file manually?

It's very easy to create a sequence file from a structure - use alignment.append_model(). One example is in http://salilab.org/modeller/FAQ.html#19

	Ben Webb, Modeller Caretaker
--
             http://www.salilab.org/modeller/
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