Skip to main page content
U.S. flag

An official website of the United States government

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1990 Sep 4;29(35):8106-11.
doi: 10.1021/bi00487a017.

Structure, stability, and receptor interaction of cholera toxin as studied by Fourier-transform infrared spectroscopy

Affiliations

Structure, stability, and receptor interaction of cholera toxin as studied by Fourier-transform infrared spectroscopy

W K Surewicz et al. Biochemistry. .

Abstract

The structure and thermal stability of isolated B and A subunits of cholera toxin, as well as the interaction of the B subunit with a ganglioside GM1 receptor, were studied by Fourier-transform infrared spectroscopy. The B subunit of the toxin is highly folded; its secondary structure consists predominantly of beta-sheets. The temperature dependence of the infrared spectrum indicates that the B subunit undergoes thermal unfolding in the temperature range between approximately 66 and 78 degrees C. Binding to the ganglioside GM1 receptor or to its oligosaccharide moiety results in only marginal, if any, change in the secondary structure of the B subunit; however, the receptor-associated subunit does show a markedly increased thermal stability. The secondary structure of the enzymatically active A subunit is less ordered and much less stable than that of the B subunit. The relatively loose folding of the A subunit is likely to be of importance for the effective membrane translocation of this subunit.

PubMed Disclaimer

Similar articles

Cited by

LinkOut - more resources