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Re: [ccp4bb]: origin definition

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On Thu, 6 Feb 2003, Bernard Santarsiero wrote:

> I have a set of phases from an MIR run in SOLVE and a potential molecular
> replacment solution of about half the structure in space group P3.  They
> have different origins in Z since it's either defined by the set of heavy
> atom positions in SOLVE, or the set of coords in the MR search model.  I
> want to compare the SOLVE phased map and the MR sfall/2Fo-Fc map.  I see
> at least two possibilities:
> 1.  mask a map region around the model of the MR solution and move it
> around the phased map; the highest CC should indicate the best overlap of
> the two maps. I think I can use RAVE to do this.
> 2.  calculate a series of phases and list the 00l's with phases. Each set
> is from a set of coords that have been translated in Z. At some point,
> these phases should match those from the SOLVE solution. 
> As for point #2, I can't seem to get sfall or sigmaa to output the
> Hendrickson-Lattman coefficients, which would be useful.  Suggestions?

You could use the MR phases to make a difference map from your MIR data, 
thus locating the heavy atom sites.  That should enable you to place your 
MIR solution on the same origin.


"Reductionism is one of those words that makes me want
    to reach for my revolver." - Richard Dawkins 
                        David J. Schuller
                        modern man in a post-modern world
                        MacCHESS, Cornell University