[ccp4bb]: dipeptide derivative for phasing

[Andreas Limacher <andreas.limacher@pharma.anbi.ethz.ch>]

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Dear all

I'd like to do heavy-atom derivatives of my crystals in order to do 
isomorphous replacement. Since I cocrystalize my protein (a cyclophilin) 
with a dipeptide (ala-pro), a possibility would be a dipeptide 
derivative. Is this feasible? Does somebody know a suitable heavy-atom 
compound; the proline is essential, the alanine can be exchanged against 
another small  aminoacid (e.g. ser, gly, val).
Thanks
Andreas