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[Stephen McMahon <smcmahon@chem.ucsd.edu>]

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Dear All, 
First of all apologies for the non-ccp4 nature of this question.
We have two proteins in the lab which are giving unusual diffraction
patterns.  They are not protein patterns but nor are they typical salt
patterns (no bright spots).  Lattice lines were evident once with one
of the proteins but all subsequent shots have failed to display any
obvious protein diffraction.
All biochemical tests indicate that the crystals are protein.
Both proteins were initially crystallised (PEG) in the presense of zinc
acetate.
One of the proteins has now been crystallised with alternative metals.
The other protein shows a dependance for the ZnOAc.
Has anyone else had similar experiances and if so were you able to
overcome this problem? 
Thanks in advance,
Stephen
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Stephen McMahon 
Dept. of Chemistry & Biochemistry, 0314 	Tel: (1) 858 822 2092
University of California, San Diego		Fax: (1) 858 534 7042
9500 Gilman Drive, La Jolla, CA 92093-0314.	smcmahon@chem.ucsd.edu
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