pH-Dependent Conformational Changes of Concanavalin A

Abstract

The pH dependence of the conformation of concanavalin A has been studied by means of optical rotatory dispersion and circular dichroism spectroscopy. At pH 2.9, 5.0, and 7.0, the major contribution to organized structure appears to be the β conformation. At pH 9.1, the conformation of concanavalin A approaches the random coil or unordered form. No evidence could be found for the presence of any significant amount of α helix. The pH of maximum precipitin-like activity of concanavalin A is paralleled by the pH dependence of the parameter b0 in the Moffitt equation.