[Fwd) ccp4 problem stuff

["Scott White" <whitesa@bcmsrv4.bham.ac.uk>]

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Dear all,

I am experiencing some problems with the refinement (fiting) step of 
AMORE. My crystal appears to be P21 (a=71.23 b=57.26 c= 116.79, 
alpha= 90 beta = 103.27 gamma= 90) with b-axis unique. The data were 
integrated and processed in mosflm and scaled in scala (R < 5%). 0k0 
reflections clearly indicate a 2-fold screw axis. AMORE appears to 
work fine giving translation search results of

alpha = -0.05  beta = 88.66  gamma = 345.08
Tx = 0.2019 Ty = 0.000 Tz = 0.4464
Cc = 24.3 Rfac = 56.3

Upon refinement (the fiting step) the value for a fractional
translation in Ty increases enormously often giving a line of
asterisks e.g. (for above example) 

alpha = -1.46 beta = 87.93 gamma = 344.55
Tx = 0.2038 Ty = ***** Tz = 0.4493
Cc = 43.3 Rfac = 54.0

This crystal is of a protein which can also grow in a tetragonal form 
where the c axis is large (over 250 Angstroms)

Could anyone offer any advice on where possible reasons for this come 
from and how best to tackle them, thanks
A.Lovering
University of Birmingham, U.K.

a.l.lovering@bham.ac.uk