circular dichroism of immunoglobulin like protein
at332 at FreeNet.Carleton.CA
Tue Sep 5 16:42:15 EST 1995
Salvatore Sechi (SSechi at helix.nih.gov) writes:
> Hello, everybody,
> I am trying to do the thermal unfolding of a protein that has two
> immunoglobulin like domain. I follow the denaturation using the CD.
> I do 5 degrees steps and I equilibrate the sample for 10 min. I scan from
> 200nm to 220nm from 22 degrees to 85. I would like to follow the
> denaturation at 217nm (maximum for the beta-sheet negative peak). Supposly
> the protein denature and the negative ellepticity at 217nm should decrease (
> less negative). Strangely the negative peak keeps encreasing. How would you
> interprete this data? Does anybody know of any other protein that behaves
> similarly? Should I go higher with the temperature?
> Hope some body can help.
> Salvatore Sechi, Ph. D.
> Laboratory of Molecular Allergy and Immunology
> E-mail: ssechi at helix.nih.gov
Is it possible that the protein might be changing from a predominantly
beta-sheet to an alpha -helical conformation? I would try extending the
range of your scans, and seeing if you get peaks at about 208 and 222 nm.
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