Protein dimerisation in SDS-gel
mick.partis at bbsrc.ac.uk
Tue Jan 23 09:15:59 EST 1996
davesmith at bioch.tamu.edu wrote:
>Lutz Essers <uj44228 at sunmail.lrz-muenchen.de> wrote:
>>My question is: Has anyone seen protein dimerisation in a SDS-gel, or are there any
>>comments or publications about this phenomenon? If so, could you please refer me.
>We asked the same question about 4 years ago when we saw dimers of our
>protein in SDS-PAGE. Since we've purified our protein, we've seen as
>high as trimers by Coommassie and hexamers when western blotting
>SDS-PAGs. The only other instance in the literature that we are aware
>of with respect to SDS-resistant dimerization is the protein that Don
>Engelman studies--glycophorin A. It just happens to also be an
>integral membrane protein. The SDS-resistant character is a result of
>residues in the transmembrane domain. ...
There is also the case of the outer membrane proteins (Porins) from E.
coli and S. typhimurium. Trimers of these are stable in SDS (even in the
presence of 8M urea), but will break down into monomers when heated. The
other notable point about porins is that although they are integral
membrane proteins, they are composed mainly of beta-structure. There are
descriptions of the SDS stability in Tokunaga, M et al. (1979) European
J. Biochem. 95: 441-448 and in Yu, F et al. (1979) FEBS Letters 100:
Mick.Partis at HRI.AC.UK Horticulture Research International
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