[phenixbb] PHENIX refine: detached sidechain atoms

Oliver King oliver.king at chem.ox.ac.uk
Thu Jun 24 04:58:12 PDT 2010


Hi Fred,

Thanks for the helpful suggestion, however it isn't just Leu residues 
it's Val, Ile, Ala, Pro and others that suffer this problem. I just 
tried to regularise the Leu and then refine again in Phenix and now both 
the CD1 and CD2 atoms have detached!
ATOM      1  N   LEU A   8      50.623 -35.571  -6.058  1.00 
52.51           N
ATOM      2  CA  LEU A   8      49.795 -35.076  -4.891  1.00 
52.71           C
ATOM      3  CB  LEU A   8      50.211 -33.647  -4.508  1.00 
49.42           C
ATOM      4  CG  LEU A   8      51.469 -33.402  -3.616  1.00 
57.61           C
ATOM      5  CD1 LEU A   8      51.910 -31.789  -3.631  1.00 
55.67           C
ATOM      6  CD2 LEU A   8      51.323 -34.077  -2.105  1.00 
53.78           C
ATOM      7  C   LEU A   8      48.247 -35.000  -5.245  1.00 
48.34           C
ATOM      8  O   LEU A   8      47.949 -34.270  -6.261  1.00 
47.33           O

Initially I thought that my monomer library was corrupt, however the 
same happens both after reinstalling Phenix and when refining on a 
different installation on another computer. I was just hoping to find a 
way to standardise the PDB file format between the two programs but 
realise that this may open a whole can of worms!

Thanks,

Olly

On 24/06/2010 10:41, Vellieux Frederic wrote:
> Hi,
>
> Can't you go to Coot before refining, and in the Model/Fit/Refine menu
> use either "Real Space Refine Zone" or "Regularize Zone" (I suspect the
> former preferred) on the residues that cause problems, before trying
> Phenix refinement again? I'd try to do that first...
>
> Fred.
>
> Oliver King wrote:
>    
>> Hi All,
>>
>> I've noticed that when refining a model in phenix.refine using a PDB
>> file from Refmac, the sidechain atoms of certain residues become
>> detached from the rest of the molecule and appear to float on their
>> own, at least when viewing in Coot. I think this is down to the format
>> of the PDB file. For example the atoms of a Leu residue from a
>> phenix.refine file which displays well is of the form:
>>
>> ATOM      1  N   LEU A   8      50.022 -34.247  -5.817  1.00
>> 58.12           N
>> ATOM      2  CA  LEU A   8      49.788 -34.905  -4.539  1.00
>> 55.84           C
>> ATOM      3  C   LEU A   8      48.339 -35.358  -4.348  1.00
>> 60.39           C
>> ATOM      4  O   LEU A   8      48.008 -36.016  -3.360  1.00
>> 68.40           O
>> ATOM      5  CB  LEU A   8      50.219 -34.011  -3.373  1.00
>> 57.98           C
>> ATOM      6  CG  LEU A   8      51.690 -34.126  -2.975  1.00
>> 65.66           C
>> ATOM      7  CD1 LEU A   8      52.014 -33.170  -1.836  1.00
>> 59.99           C
>> ATOM      8  CD2 LEU A   8      52.020 -35.566  -2.594  1.00
>> 68.57           C
>>
>> where as from a Refmac PDB which also behaves well, it is of the form:
>>
>> ATOM      1  N   LEU A   8      50.453 -35.722  -5.617  1.00
>> 20.00           N
>> ATOM      2  CA  LEU A   8      49.649 -35.131  -4.482  1.00
>> 20.00           C
>> ATOM      3  CB  LEU A   8      50.190 -33.735  -4.147  1.00
>> 20.00           C
>> ATOM      4  CG  LEU A   8      51.461 -33.755  -3.275  1.00
>> 20.00           C
>> ATOM      5  CD1 LEU A   8      52.556 -32.768  -3.741  1.00
>> 20.00           C
>> ATOM      6  CD2 LEU A   8      51.082 -33.546  -1.799  1.00
>> 20.00           C
>> ATOM      7  C   LEU A   8      48.166 -35.063  -4.824  1.00
>> 20.00           C
>> ATOM      8  O   LEU A   8      47.822 -34.257  -5.568  1.00
>> 20.00           O
>>
>> but after refinement in phenix it becomes
>>
>> ATOM      1  N   LEU A   8      50.734 -35.936  -5.935  1.00
>> 54.45           N
>> ATOM      2  CA  LEU A   8      49.846 -35.185  -4.892  1.00
>> 51.89           C
>> ATOM      3  CB  LEU A   8      50.377 -33.761  -4.516  1.00
>> 51.22           C
>> ATOM      4  CG  LEU A   8      51.550 -33.730  -3.431  1.00
>> 59.27           C
>> ATOM      5  CD1 LEU A   8      52.457 -32.407  -3.635  1.00
>> 60.88           C
>> ATOM      6  CD2 LEU A   8      51.120 -34.090  -1.879  1.00
>> 55.50           C
>> ATOM      7  C   LEU A   8      48.268 -35.042  -5.221  1.00
>> 47.92           C
>> ATOM      8  O   LEU A   8      47.989 -34.282  -6.195  1.00
>> 47.32           O
>>
>> and the CD2 atom is now too far away to be part of the residue in Coot
>>
>> Is there an easy way to convert a PDB from Refmac into one which will
>> behave itself when put through phenix.refine? I've tried using
>> phenix.pdb_tools and also putting the model through Molprobity and
>> hoping that that the output would be corrected.
>>
>> Thanks,
>>
>> Olly King
>>
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>>
>>
>>      
>    



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