Re: [AMBER] Problem related to Missing amino acids in pdb

From: Sindrila Dutta banik <sindrila.duttabanik.yahoo.com>
Date: Wed, 15 Jun 2011 11:41:57 +0530 (IST)

Hello!


I have a crystal structure of an enzyme (HisRS) which is tetramer. The residues between 185 to 228 are missing for all chains. How to manage this issue?

If I load the pdb file as it is then it forms a bond between the residue 185 and 228 which is unnatural. A part of the pdb file showing the coordinate of residue 185 and residue 228 is shown as follows:
  
ATOM   1798  H   LEU A 185       1.645  44.592   6.981  1.00  0.00           H 
ATOM   1799  N   TYR A 228     -12.077  46.733  12.305  1.00 60.84           N 
 
If I add ‘TER’ in between the coordinates of residue 185 and coordinate of residue 228 then leap consider the 185 residue as C-terminal residue and 228 residue as N-terminal residue and creates one additional positive charge for the amino croup of 185 residue and a negative charge for the carboxylic acid group of 228 residue. A part of the pdb file showing the coordinate of residue 185 and residue 228 in the modified pdb file is shown as follows:

ATOM   1798  H   LEU A 185       1.645  44.592   6.981  1.00  0.00           H
TER
ATOM   1799  N   TYR A 228     -12.077  46.733  12.305  1.00 60.84           N 
 
Now I want to make the carboxylic acid group (-COO-) of 185 residue and amino group of (-NH3+) residue 228 as neutral. How to do this? I also want to know in general what is used in such cases.  
  
With best regards
Sindrila   
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Received on Tue Jun 14 2011 - 23:30:04 PDT
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