Re: [ccp4bb] R/Rfree problem

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

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Subject: R/Rfree problem
From: Á¶±âÁØ c-azna {- at -} KOREA {- dot -} AC {- dot -} KR
Date: 2012-01-19

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From: Artem Evdokimov artem {- dot -} evdokimov {- at -} GMAIL {- dot -} COM
Date: 2012-01-19

Subject: Re: R/Rfree problem
From: Garib N Murshudov garib {- at -} MRC-LMB {- dot -} CAM {- dot -} AC {- dot -} UK
Date: 2012-01-19

You can try zanuda from York's site.

www.ysbl.york.ac.uk/YSBLPrograms/index.jsp

It may help. It may be that you have a twinned crystal. As far as I know best available test for twinning is L-test (truncate produces this test). When you go from P1 to P212121 if L-test shows increased twinning then it may mean that you are overmerging.

regards and I hope it helps

Garib

On 19 Jan 2012, at 12:06, Á¶±âÁØ wrote:

> Dear all,
>
> I have a data, and it has R/Rfree problem.
> The data could be processed as P212121 and P1.
> The resolution was 2.9, and unit cell parameters were a=73.527, b=90.035, c=237.980, ¥á=¥â=¥ì=90 and a=73.709, b=90.099, c=238.172, ¥á=89.939, ¥â=89.945, ¥ì=89.993 for P212121 and P1, respectively.
> R/Rfree was 22.3/29.4 for P1 after several refinements.
> However, I couldn¡¯t decrease R/Rfree below 30.0/37.6 for P212121.
> There were almost no differences on monomer structure and crystal packing between P212121 and P1 after MR, and the electron densities followed trace of peptide chain well.
> Can anybody suggest me about this problem?
>
> Thank you.
> Ki Joon Cho
>
>

Garib N Murshudov
Structural Studies Division
MRC Laboratory of Molecular Biology
Hills Road
Cambridge
CB2 0QH UK
Email: garib@mrc-lmb.cam.ac.uk
Web http://www.mrc-lmb.cam.ac.uk

CCP4bb navigation

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

Previous message:
Subject: R/Rfree problem
From: Á¶±âÁØ c-azna {- at -} KOREA {- dot -} AC {- dot -} KR
Date: 2012-01-19

Next message:
Subject: Re: His Purification
From: Artem Evdokimov artem {- dot -} evdokimov {- at -} GMAIL {- dot -} COM
Date: 2012-01-19