Re: [ccp4bb] Lots of noise in structure

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

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Subject: Re: Lots of noise in structure
From: Gerard DVD Kleywegt gerard {- at -} XRAY {- dot -} BMC {- dot -} UU {- dot -} SE
Date: 2010-01-06

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Subject: Re: Lots of noise in structure
From: "George M {- dot -} Sheldrick" gsheldr {- at -} SHELX {- dot -} UNI-AC {- dot -} GWDG {- dot -} DE
Date: 2010-01-06

Subject: Re: Lots of noise in structure
From: Eleanor Dodson ccp4 {- at -} YSBL {- dot -} YORK {- dot -} AC {- dot -} UK
Date: 2010-01-06

The obvious Q is whether there is some additive in the crystallisation
or cryo which could be showing up in the maps..

But in such a high symmetry space group is it possible that the blobs
are on some symmetry axis? I sometimes observe awful holes or peaks on 3
fold axes, where I think any "noise" feature isexaggerated by the symmetry.

Eleanor

Rajan wrote:
> Dear All,
>
> Happy New Year
>
> I am working with a 2.06 Ang resolution structure in F432 space group and
> further using REFMAC (also tried Phenix) program for refinement of my
> model.
>
> Every thing in the structure seems good, R factor/ R free= 18.59/20.77 but
> the structure is too noisy (blobs of difference Fourier with red as well as
> green density).
>
> As such electron density is looking good for the protein part.
>
> Is there any parameter which i had to check.
>
> Thanking you in advance
>
> Rajan
>

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

Previous message:
Subject: Re: Lots of noise in structure
From: Gerard DVD Kleywegt gerard {- at -} XRAY {- dot -} BMC {- dot -} UU {- dot -} SE
Date: 2010-01-06

Next message:
Subject: Re: Lots of noise in structure
From: "George M {- dot -} Sheldrick" gsheldr {- at -} SHELX {- dot -} UNI-AC {- dot -} GWDG {- dot -} DE
Date: 2010-01-06