Structural changes in the proteins from two species of the genus vigna by effect of different treatments

A study of the thermal treatment effect on the protein structure of the rice bean and cowpea bean was conduced. The protein was isolated by isoelectric focusing and electrophoretic pattern, FT-IR and FT-Raman spectroscopy were used for their characterization. The results showed that in both species the thermal treatment originate modifications on the conformational structure modifying the secondary structure, disorder level and agregation fractions. The FT-IR and FT-Raman spectros indicate that the main secondary structure is the protein of both species, was the β-sheet with a smaller contribution of the α-helix structure. The structure 310 helix and the sulfhydril groups were detected in the protein of both species, in addition the presence of some aminoacids also were observed (Cys, Lys, Trp, Phe, Tyr and Met). The electrophoretic pattern showed a significantl reduction in the number of high molecular weight subunits by effect of thermal treatment and isolation process, two hight molecular weight bands are mantained before and after treatments (23 kDa and 50 kDa), these fractions could be a stable subunits and common ancestor in both species.

Keywords: Vigna unguiculata, Vigna umbellata, IR, Raman, spectroscopis.