Re: [ccp4bb] phased MR

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

Previous message:
Subject: Re: phased MR
From: Gerard Bricogne gb10 {- at -} GLOBALPHASING {- dot -} COM
Date: 2008-11-04

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Subject: Group Leader Position in Structural Biology at EMBL Heidelberg
From: Christoph Mueller christoph {- dot -} mueller {- at -} EMBL {- dot -} DE
Date: 2008-11-04

Subject: Re: phased MR
From: Pete Meyer pameyer {- at -} MCW {- dot -} EDU
Date: 2008-11-04

For what it's worth, I'd try to get as much as possible out of the
experimental phases before going on to phased MR.

> I have SeMet MAD data to 3.6A that gives decent looking anomalous
> difference peaks, looks stable in mlphare, and produces solvent
> flattened maps to 2.8A in DM that look like the density might be a
> sensible shape - wrt solvent gaps etc - but not interpretable so far (I
> will be trying phasing in SHARP, CNS etc).

One thing to try would be the bp3/pirate combination for
phasing/density modification. With some datasets, this works very well
(in my hands, not with all datasets).

Another (which you've probably already tried) would be to check the MAD
maps after solvent flattening, but before phase extension, as well as
comparing the MAD maps to SAS maps.

It's probably also worth checking the dispersive difference peaks, and
cross checking them with the anomalous difference peaks. You should get
the same peaks out, but it'll let you guess as the relative phasing
signal for dispersive vs anomalous (but so will comparing MAD vs SAS).

> Any advice gratefully received.

Hopefully I'm not giving you too many suggestions you've already tried.

Pete

CCP4bb navigation

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

Previous message:
Subject: Re: phased MR
From: Gerard Bricogne gb10 {- at -} GLOBALPHASING {- dot -} COM
Date: 2008-11-04

Next message:
Subject: Group Leader Position in Structural Biology at EMBL Heidelberg
From: Christoph Mueller christoph {- dot -} mueller {- at -} EMBL {- dot -} DE
Date: 2008-11-04