Dear Linda, If your molecule is not very big, your cell is not very big, you
have an approach to modern in-house X-ray facility, your crystal diffract
reasonably well ( :-\ ) you can try S phasing. If you will be able to measure
accurate data, S anomalous phasing at 1.5417 Angstrom of Cu radiation
may work like charm (it is usually a case in my hands). In addition, if it
happened that you have also couple of Cl etc. it will support phasing even more.
I prefer to test S-SAD cases with shelxC/D/E pipeline under HKL2MAP GUI.
Happy holidays
FF
Dr Felix Frolow
Professor of Structural Biology and Biotechnology, Department of Molecular
Microbiology and Biotechnology
Tel Aviv University 69978, Israel
Acta Crystallographica F, co-editor
e-mail: mbfro...@post.tau.ac.il
Tel: ++972-3640-8723
Fax: ++972-3640-9407
Cellular: 0547 459 608
On Dec 26, 2012, at 20:33 , Linda Olson lol...@mcw.edu wrote:
Dear All,
I have read a recent paper by Salgado et al about using non-auxotrophic
E.coli to incorporate SeCys into recombinant protein for phasing purposes.
Does anyone have a source for Selenocysteine? I have also seen a paper by
Schaefer et al which uses nitric acid treated elemental Se for a sulfur
surrogate to generate Se-labeled protein. Has anyone else tried this? My
proteins are rich in Cys and tend to lack Met so the prospect of labeling cys
is very attractive.
Thanks,
Linda
Linda Olson, PhD
Research Scientist II
Dept Biochemistry
Medical College of Wisconsin
8701 Watertown Plank Rd
Milwaukee, WI 53226
phone: 414-955-8545
fax: 414-456-6510
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