[ccp4bb] Choosing weighing term

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

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Subject: Choosing weighing term
From: conancao conan_cao {- at -} HOTMAIL {- dot -} COM
Date: 2009-04-01

Dear All:

Hi. I have a question about selecting weighing term during restrained refinement using Refmac5 of CCP4 packages.

For a 300kDa homodimer protein structure at 2.5A, 91% complete. I obtain optimal R and Rfree by using NCS tight restraints of the peptides of the two monomers. Weighing term 0.15 gives (R=0.22, Rfree=0.28) and weighing term 0.1 gives(R=0.23, Rfree=0.28). Higher weighing term gives larger difference between R and Rfree.

Is there a criteria or special range of choosing weighing term? Is weighing term 0.1 too small? I read the references by Ian Tickle (Acta Cryst D, 1998 and 2000)on R and Rfree ratio, those helped a lot but I still do not know the key of weighing term.

Thanks so much.

Best,

Hongnan Cao

Biochemistry Department

UC Riverside

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CCP4bb navigation

CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Building structure in COOT
From: Liew Chong Wai CWLiew {- at -} NTU {- dot -} EDU {- dot -} SG
Date: 2009-03-31

Next message:
Subject: Re: Building structure in COOT
From: David Cobessi David {- dot -} Cobessi {- at -} IBS {- dot -} FR
Date: 2009-04-01