Re: [ccp4bb] NOT Job Advertisement but model refinement

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

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Subject: Re: Job Advertisement: Research Scienstist (Germany)
From: atul kumar atulsingh21985 {- at -} GMAIL {- dot -} COM
Date: 2010-06-17

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Subject: Re: Not a Job Advertisement
From: "George M {- dot -} Sheldrick" gsheldr {- at -} SHELX {- dot -} UNI-AC {- dot -} GWDG {- dot -} DE
Date: 2010-06-17

Subject: Re: NOT Job Advertisement but model refinement
From: Vellieux Frederic Frederic {- dot -} Vellieux {- at -} IBS {- dot -} FR
Date: 2010-06-17

This has been told (written, in fact) on this bb many times. The purpose
of refinement is not to bring the R-factor down, but to obtain a model
that satisfies "best" all available data (including "biochemical" data).

Anyway, as to what you can do: it's always possible to question the
choice of TLS groups. I do not know how you select yours. What I
personally do is to connect to the TLSMD server, lauch the computation,
then have a look at the output curve. There is a steep descent at first,
and (usually) a break in the curve. This break in the curve I use to
tell me how many TLS groups to be used during refinement.

One can always change the refinement program to see if an improved
geometry together with more appropriate R and R-free values can be
obtained (both at the same time).

But you do not give much information on how you have built and refined
your model so far... Also, sometimes automated model rebuilding programs
give excellent results.

Fred.

atul kumar wrote:
> dear all
> I am trying to solve structure of data set at 1.9 A,r merge 9.3,it
> belongs to space group P3221 unit cell 160.78 157.32 135.62 90.0 90.0
> 90.0,i has no NCS ,i did tls as well but after water addition the r
> factor and r free is stuck at 22 and 25 respectively. kindly guide me
> how can i bring down the R factor.
>
> Thankin you.
>
> Regards
> Atul

CCP4bb navigation

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

Previous message:
Subject: Re: Job Advertisement: Research Scienstist (Germany)
From: atul kumar atulsingh21985 {- at -} GMAIL {- dot -} COM
Date: 2010-06-17

Next message:
Subject: Re: Not a Job Advertisement
From: "George M {- dot -} Sheldrick" gsheldr {- at -} SHELX {- dot -} UNI-AC {- dot -} GWDG {- dot -} DE
Date: 2010-06-17