A circular dichroism study of (+) gossypol binding to proteins

Abstract

The circular dichroism bands of (+) gossypol in the spectral region 300-400 nm have been shown to be sensitive to interactions with proteins. Using CD spectroscopy, gossypol has been shown to interact with lactate dehydrogenase, malate dehydrogenase, alkaline phosphatase, lysozyme, protamine and poly-L-lysine. Binding to proteins generally results in a pronounced red shift of the long wavelength CD band (^∼ 380-430 nm) accompanied by a reduction in ellipticity. The changes in spectral parameters of the ¹L_b binaphthyl transtion may reflect a distortion from a nearly perpendicular gossypol conformation, on binding to proteins.