Re: [ccp4bb]: Summary: Molecular Replacement woes!

["Eleanor J. Dodson" <ccp4@ysbl.york.ac.uk>]

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schakrav wrote:
> 
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> 
> Wrong space group asssignment being almost unanimously suggested i did rethink
> the issue. Matthew's calculation suggests one molecule per AU. I looked at the
> data again and confirmed the existence of only one screw axis. it is
> definitely not p212121. but i am not so sure it is orthorhombic anymore. i
> dont have any arguments against the possibility of monoclinic. i have indexed
> and scaled the data in p21 and as expected the completion suffers because we
> assumed it was orthorhombic for the data collection strategy. Havent had much
> success with molecular replacement yet.
> I will try some of the other MR softwares suggested.
> I havent included everyone's suggestions in the summary but I sincerely thank
> everyone for your input.
> cheenu.
> 
> Srinivas Chakravarthy
> Colorado State University
> Fort Collins
> CO-80521
\


 If you use Amore from CCP4i it is rather easy to test whether it is P
2i 2i 2i 
for all 8 posibilities: P222, P21 2 2, P21 21 2, P21 21 21, P 2 21 2,
etc etc..

 The rotation solutions are the same for each, and then you run the
translation search in all possibilities and see if one gives a signif
better result. The difficulty is that all spacegroups will be "correct"
for the reflections where h & k & l are even, and others correct for
subsets of data with h or k or l even .

 Eleanor