[ccp4bb]: P21/P2 space-group ambiguity

[ZELWER Charles <zelwer@cnrs-orleans.fr>]

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Dear all,

We have the case of a monoclinic crystal with 0k0 systematic extinctions
observed for k comprised between 3 and 15 and b = 70 Angstr. Other 0k0
reflexions have not been recorded. The anomalous pattersons for two
different anomalous scatterers support a P2 rather than a P21 space-group
(all the peaks are in the y=0 section and the y = 0.5 section contains only
weak peaks). Does anybody know well documented examples for which such a
situation has been encountered? It would make us more confident in our
interpretation. Any reference would be well appreciated.

Best Regards

Charles Zelwer


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 Charles ZELWER
 Centre de Biophysique Moléculaire
 Equipe de Cristallographie Biologique
 C.N.R.S.,  rue Charles Sadron
 45071 ORLEANS Cedex 2 (France)

phone: +33 2 38 25 78 03
fax:   +33 2 38 63 15 17
Email: zelwer@cnrs-orleans.fr
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