Studies on the conformation of α-globulin fromSesamum indicum L. in cationic and nonionic detergents

The circular dichroic spectra of α-globulin fromSesamum indicum L. was recorded in the presence of cetyltrimethyl ammonium bromide, Triton X-100 and Brij-36T. The protein in 0.2 M phosphate buffer pH 7.4 had about 25% Β-structure and 5% α-helix, the rest being aperiodic or irregular structure and a-helix, structure was increased by cationic detergent cetyl trimethyl ammonium bromide. But, the increase in α-helix content was much less than that induced by an anionic detergent, sodium dodecyl sulphate. In non-ionic detergent like Brij-36T and Triton X-100, specific Β-structures like II-Β and I-Β were formed along with changes in α-helical and aperiodic structures. These results suggest that the protein has a fairly labile quaternary structure. Part of this work was presented at the Second FAOB Congress and Golden Jubilee Meeting of the Society of Biological Chemists (India) held during December 14–18, 1980 at Bangalore, India (Indian J. Biochem. Biophys.) and the work was done at the Biochemistry Department, Brandeis University, Waltham, Massachusetts 02254 USA.