Protein solution conditions

Daniel W. Bearden (bearden@manta.chbr.noaa.gov)
Thu, 2 Jul 1998 17:33:36 -0400

Hello,
I am looking for tips on solvent conditions for protein solutions. I
wonder if anyone has a reference or set of standard (?) things to try when a
protein is not cooperating for NMR. (I think this is analogous to the things
that people do to try to get crystals to form for X-ray crystallography!)
My protein (50 residues) seems to give very nice peaks in acid (pH very
low, and undetermined, but probably < 4), but things get worse as the pH is
raised to 5.5 or near 7. By worse, I mean that the 'index' I am using is the
lack of assignable side chains for S, D, N, C, W, F, Y and H (I can get about 7
out of 14 systems at low pH). The CD spectrum shows good results over this
whole pH range, so I am perplexed (I have not ruled out dimerization, etc, but
the CD does not seem to show it).
All hints and directions would be greatly appreciated. I am not a
biochemist, so go easy on me!

Thanks,
Dan

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Daniel W. Bearden                       Phone:  (803) 762-8527
National Ocean Service	                FAX:    (803) 762-8700
219 Ft. Johnson Rd.        e-mail: bearden@manta.chbr.noaa.gov
Charleston, SC  29412
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