Have you thought about phasing off the sulfurs? This is quite a common
technique nowadays.
Jim
On Tue, 27 May 2008, Joe Smith wrote:
Dear all,
Sorry for an off-topic query.
I have been unable to crystallize a Se-met containing protein (8 Met
in 206 amino acids) in the native crystallization condition ( 0.1 M
Tris pH 8.5, 1.2 M K-Na-tartrate; Theoretical pI of protein is 8.4).
As expected, solubility of Se-Met containing protein is little less
than the wild type. Other than seeding, i don't know what else I
should try for obtaining a Se-met crystal for phasing. Can I mutate
some of the exposed Met (based on secondary structure prediction and
homologous structure) to Ala as I feel I don't really need 8 Se for
phasing 208 aa long polypeptide. I want to know what generally one
should do when Se-Met containing proteins fail to crystallize.
Thanks in advance.
Joe
PS: Since, protein contains 3 Cys residues.. I am also planning to try
my luck with heavy atom compounds containing Hg.
