Re: software to convert XYZ format to PDB ?
- From: Eric Bennett <ericb<<at>>pobox.com>
- Subject: Re: software to convert XYZ format to PDB ?
- Date: Fri, 02 Jul 2004 11:09:12 -0500
Michel Petitjean wrote:
To: chemistry<<at>>ccl.net
Subject: CCL:software to convert XYZ format to PDB ?
Konrad Hinsen <hinsen<<at>>cnrs-orleans.fr> wrote:
If I had to do this (fortunately I don't), I'd first identify the
peptide planes as patterns of pairwise distances (they are quite
rigid). I'd then identify the sidechains atom by atom starting from the
C-alphas, again by distance criteria. Not a trivial task, but not an
impossible one either.
Sure... if you have the side chains ! (were not indicated in the example)
It needs other assumptions: true residues, no HETATM, lexicographical
ordering coherent with the PDB conventions...
There are programs (such as ARP/wARP) which start with NO atom information, not
even coordinates, and can correctly build a protein structure based on an
electron density map using pattern recognition techniques. The ambiguities
there, such as ASP vs. ASN, are not present when you know the elements, as we do
here. ARP/wARP is also gaining ligand building capabilities and already handles
water molecules.
ARP is part of CCP4 so you get source code with it.
http://www.embl-hamburg.de/ARP/
Of course if you have any unexplained data (whether electron density or known
atom positions) that do not fit the pattern of an amino acid, you can just leave
them alone and inform the user.
--
Eric Bennett, Center for Drug Design, U of Minnesota