Hi,
I assume Se-Met is not possible for your protein?
You don't say how well (or poorly) your native crystals diffract.
Increasing number of people are getting their phases by S SAD.
With such affinity to high NaCl concentrations, you could also try high
salt (NaCl, NaBr, RbBr etc,) soaks for phasing.
Good luck,
Nukri
Ruslan Sanishvili (Nukri), Ph.D.
GM/CA-CAT, Bld. 436, D007
Biosciences Division, ANL
9700 S. Cass Ave.
Argonne, IL 60439
Tel: (630)252-0665
Fax: (630)252-0667
[log in to unmask]
-----Original Message-----
From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of
Priyank Maindola
Sent: Thursday, June 28, 2007 12:28 PM
To: [log in to unmask]
Subject: [ccp4bb] heavyatom soaking problem
Hello all,
I am struggling with getting the phases out for my protein. Heavyatom
database shows that only mercury and samarium have the binding motifs in
it.
Sodium iodide soak is killing the crystal even as less as 0.2 Molar
concentration for 30sec.
With Potassium iodide crystal is okay upto 0.75M for 1 & a half min but
the incorporation is not at relevent sites.(Iodide signal is not
distinct and is weak) Hg & Au salts precipitate it.
With Pt signal is weak.
Somewhere I read that high salt causes problems for heavy atom to bind
to protein.My protein needs high salt for stability (750mM NaCl)
Please help with some suggestion!!
|