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Re: [ccp4bb] How to refine large moleculars?
 

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CCP4bb <-- 2008 <-- January 2008 <-- 07 January 2008
Previous message:
Subject: complement on how to refine large moleculars.
From: Yongchao Li yond_lee {- at -} YAHOO {- dot -} COM
Date: 2008-01-07 		Next message:
Subject: how to model this density?
From: Jiamu Du jiamudu {- at -} GMAIL {- dot -} COM
Date: 2008-01-07


Subject: Re: How to refine large moleculars?
From: Tim Gruene tg {- at -} SHELX {- dot -} UNI-AC {- dot -} GWDG {- dot -} DE
Date: 2008-01-07
Depending on your data quality and the nature of the crystal it might be
that you cannot reduce R/Rfree any further.
Low R/Rfree is not the goal of refinement and model building - at least
not for the humans doing it. The goal is to get as good a model as
possible, and if your data are not very good, or also for various other
possibilities you might not be able to improve the statistical guidelines.

I am not suggesting you should stop refining now - but without knowing you
data/ resolution/ data statistics it is very difficult to give an answer.

Cheers, Tim

--
Tim Gruene
Institut fuer anorganische Chemie
Tammannstr. 4
D-37077 Goettingen

GPG Key ID = A46BEE1A


On Mon, 7 Jan 2008, Yongchao Li wrote:

> I have a large molecule to refine.There are about three thousand residues in one asymmetric unit.
> Except for the lack of electron densities in several places, where the
> loops have been deleted, the rest parts fits well with density. But the R free and R work are all beyond 0.30 (R free = 0.35, R work = 0.30).
> I don't know how to reduce them.
> Can anyone give me some ideas?
>
> Thank you!
>
>
>
> ---------------------------------
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CCP4bb navigation

CCP4bb <-- 2008 <-- January 2008 <-- 07 January 2008
Previous message:
Subject: complement on how to refine large moleculars.
From: Yongchao Li yond_lee {- at -} YAHOO {- dot -} COM
Date: 2008-01-07 		Next message:
Subject: how to model this density?
From: Jiamu Du jiamudu {- at -} GMAIL {- dot -} COM
Date: 2008-01-07


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