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Re: [ccp4bb] torsion restraints and phi/psi |
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CCP4bb navigationCCP4bb <-- 2007 <-- November 2007 <-- 07 November 2007Subject: Re: torsion restraints and phi/psi From: Edward A Berry eaberry {- at -} LBL {- dot -} GOV Date: 2007-11-07 > Dear All, > > I wonder about the exact use of torsion restrains and the effect > on phi/psi/w validation. > ---- > > a) does refmac restrain phipsi at all (except vdw repulsion > which does not bias them otherwise)? > Isn't it the case that vdw interactions are turned off between atoms in a residue, and perhaps with the residues before and after? Otherwise positional refinement would in fact tend to drive the residues into the rama-allowed region? Might it be a good idea to use torsion restraints, or intra-residue vdw repulsion, in the last stage of refinement after calculating an unbiased ramachandran plot; especially in low-resolution problems where we need all the restraints we can get? Ed CCP4bb navigationCCP4bb <-- 2007 <-- November 2007 <-- 07 November 2007 |
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