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[ccp4bb]: data processing (summary)

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Dear all,

here is a summary of the tips I received last week regarding my data
processing troubles (reminder: indexing and integration show center
orthorombic, or monoclinic, but scaling goes awry except for P1 with two 90
degree angles). Despite being specific for my problem, some of them might
turn useful for the inexperienced crystallographer.

i)	P1 90/90 can actually be true, it's the internal symmetry that defines
crystal system and space group

ii)	try a different program (d*TREK, xds, Mosflm)

iii)	unique axes could have been mixed up, swap them around

iv)	wrong beam position can lead to misindexing by one

v)	scale in P1, make mtz and use hklview to look for symmetry

vi)	calculate self-rotation function, and check for symmetry

vii)	crystal may be twinned

viii)	a few alternative lattices were also suggested

Thanks to everybody again,


Carlo Ciatto		     Tel. 0041 1 6356563
Biochemistry Institute    University of  Zuerich
190 Winterthurerstrasse 8057  Zurich Switzerland