AFAIK, protein must be very soluble if you want to grow a crystal.
20-30 mg/ml (? I have no experience in making those crystalls, that is what
I think).
you can check literature on HIV integrase - a very tough protein to
crystallize. They had to screen lots of mutants to make it soluble (only the
core domain at first; by now two-domain fragments of integrase have been
crystallized as well).
One smart way to screen for protein solubility is to make fusion with CAT .
Soluble mutant gives higher resistance to Cm:
Protein Sci 1999 Sep;8(9):1908-11 A simple in vivo assay for increased
protein solubility.
Maxwell KL, Mittermaier AK, Forman-Kay JD, Davidson AR.
never tried it.... but looks interesting
Proc Natl Acad Sci U S A 1995 Jun 20;92(13):6057-61 Catalytic domain of
human immunodeficiency virus type 1 integrase: identification of a soluble
mutant by systematic replacement of hydrophobic residues. Jenkins TM,
Hickman AB, Dyda F, Ghirlando R, Davies DR, Craigie R.
that is actually the key work, which led to crystallization of the catalytic
domain of integrase.
good luck,
Peter
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