Cereal Chem 50:114 - 121. | VIEW
Comparison of Conformations of 7S and 11S Soybean Globulins by Optical Rotatory Dispersion and Circular Dichroism Studies.
I. Koshiyama and D. Fukushima. Copyright 1973 by the American Association of Cereal Chemists, Inc.
Conformational studies of the 7S and the 11S globulins, the major storage proteins of soybean seeds, were made by optical rotatory dispersion (ORD) and circular dichroism (CD). Between 200 and 250 nm., CD spectra of both proteins were fairly similar, and their experimental CD patterns between 210 and 240 nm. agreed well with those calculated from ORD parameters a0 and b0. Their secondary structures appeared analogous, and the contents of alpha-helix, beta-structure, and random coil in both proteins were estimated to be approximately 5, 35, and 60%, respectively. However, the formation of alpha-helix accompanying its dissociation into subunits and changes of molecular ellipticity by treatment with sodium dodecyl sulfate was less in the 11S than those in the 7S globulins. Furthermore, CD spectra between 250 and 320 nm. differed between them. These facts suggested that their tertiary structures differed to some extent, and that the state of tyrosyl residues were different between the two proteins.