Acetylation of faba bean legumin: conformational changes and aggregation

Abstract

The effect of progressive acetylation upon the conformation of the 11S globulin legumin from faba bean has been studied using chemical analysis, UV, fluorescence and CD spectroscopy, viscometry and analytical ultracentrifugation. The modification did not induce complete dissociation of the oligomeric protein. Only 30% of the protein was found to be a dissociated 3S subunit after excessive acetylation, whereas 70% was a dimeric legumin aggregate with a molecular mass of about 700 kDa. The aggregation of the highly modified legumin in high‐ionic‐strength buffer solution leads to soluble higher legumin oligomers. The acetylation resulted in a moderate molecular expansion of legumin due to a changed tertiary structure, whereas the far‐UV circular dichroism spectra did not provide definitive evidence of a decrease in domain‐stabilizing β‐sheet conformations in their secondary structure. © 2000 Society of Chemical Industry

Isolation and study of the functional properties of pea proteins

“…It should be mentioned that according to literary date, the functional properties of legumins could be improved by modification [18,19].…”

Improved emulsifying properties of soy proteins by acylation with saturated fatty acids

“…A sharp increase in the degree of modification (49.73-99.45%) was observed in the 11S acylated with medium (10C-12C) and long chain (14C-18C) fatty acids, indicating a dissociation of the oligomeric structure of 11S subunits, due to the unfolding of tightly folded polypeptides in native structure. An increase in the acylation level is due to conformational changes of the protein, which result in a rather unfolded structure and an increased availability of reactive residues (Schwenke, Knopfe, Seifert, Gornitz, & Zirwer, 2001). Acylation initiates the unfolding of the native protein structure, and exposes buried amino groups to react with the interface.…”

Reflections about the functional potential of legume proteins A Review

“…Although the group specificity of the different reagents may be limited, it can be increased by careful selection of the reaction conditions. Thus, increasing or decreasing charge and hydrophobicity results in modified legume proteins with a large spectrum of physico-chemical and functional properties (see e. g. [39,[73][74][75][76][77][78][79][80][81][82]). Thus, increasing or decreasing charge and hydrophobicity results in modified legume proteins with a large spectrum of physico-chemical and functional properties (see e. g. [39,[73][74][75][76][77][78][79][80][81][82]).…”

“…The changes in the interfacial and emulsifying properties [82][83][84] can in these cases be attributed to the modified surface properties of the proteins. In contrast to succinylation, acetylation causes mainly an aggregation (oligomerization) of legumin due to the markedly increased hydrophobicity [81]. The latter takes place most efficiently, when the most part (85-95%) of NH 2 -groups were acylated and the following succinylation of OH-groups of hydroxyamino acids additionally contributes to the electrostatic repulsion effects of the polypeptide chains.…”