[ccp4bb] weird thing about MR

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

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Subject: call for proposals for beamtime at BM14/ESRF June/July 2007
From: "Martin A {- dot -} Walsh" walsh {- at -} ESRF {- dot -} FR
Date: 2007-04-27

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Subject: Re: weird thing about MR
From: Eleanor Dodson ccp4 {- at -} YSBL {- dot -} YORK {- dot -} AC {- dot -} UK
Date: 2007-04-27

Subject: weird thing about MR
From: Yi Xue yi-xue {- at -} NORTHWESTERN {- dot -} EDU
Date: 2007-04-27

Dear all:

I have a dataset diffracted to about 3A, and it is supposed to be
protein/DNA complex. The spacegroup could be I4, I422, I222, or F222.
I used the protein structure to start molecular replacement. There are
three copies of complexes if assuming I422 symmetry. For the search of the
first copy (phaser), the top solution had very good RFZ (7.4) and TFZ
(18.1), meanwhile, there were total 44 good solutions, with RFZ>7 and
TFZ>14. However, subsequent rigid body refinment of the top solution gave
very high R and Rfree of around 80%. I tried all choices of space groups,
briefly, they behaved similarly: MR found good solutions, R and Rfree were
weirdly high.

I was thinking maybe the spacegroup is wrong, I checked the data very
carefully, and it seemed that the spacegroups I had chosen should be right.
Any comments are highly appreciated.

Best
Yi

CCP4bb navigation

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

Previous message:
Subject: call for proposals for beamtime at BM14/ESRF June/July 2007
From: "Martin A {- dot -} Walsh" walsh {- at -} ESRF {- dot -} FR
Date: 2007-04-27

Next message:
Subject: Re: weird thing about MR
From: Eleanor Dodson ccp4 {- at -} YSBL {- dot -} YORK {- dot -} AC {- dot -} UK
Date: 2007-04-27