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Re: [ccp4bb]: p61 vs p65 flipped
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hay.dvir@weizmann.ac.il wrote:
>
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> Dear Ed,
>
> > I'm trying to find Se sites in MAD data from crystals of space group p61 or
> > p65. I was under the impression that the Patterson maps should be the same
> > for both and that I therefore only needed to solve the Pattersons once.
> > Experimental Patterson maps from peak data look the same for both. However,
> > Solve is giving me different solutions for p61 compared with p65.
>
> Difference patterson map should look the same, since the Fourier
> coefficients in the patterson function are being squared. Therefore, from
> the patterson you get two equivalent substructure solutions related to
> each other by inversion.
> In most programs you should try both solutions to phase your
> protein amplitudes. However, SOLVE has a built in automated routine to
> guess the correct hand of your substructure. Thus, for a given space group
> you provide with SOLVE you would get only one solution which probably
> corresponds to the correct hand (as much as solve could guess) of the
> substructure. However, if one of the space group you gave p61 or p65 are
> correct, you should expect significantly different phase statistics and
> maps.
Actually phase statistics are the same for eaither P61 or P65 providing
the solutions correspond..
Maps look different though and all scoring systems will reflect this..
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Eleanor J.Dodson, York Structural Biology Laboratory,
Chemistry Department,
University of York, Y01 5DD Heslington, U.K.
Tel: Work: +44 (1904) 32 82 53 Home +44 (1904) 42 44 49
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