The effect of the allosteric regulation on the catalytic activity of fructosyltransferase studied via molecular dynamics simulations†

Fructosyltransferase (FTase) is a key glycosidase with hydrolytic and transglycosylation functions that can utilize sucrose to generate oligofructose (FOS), which is extremely important in the food industry as well as in plants and microorganisms. However, there remain significant gaps in our understanding of the catalytic mechanism of FTase, particularly regarding the effect of regulatory mechanisms of residues on enzyme catalytic activity. In this study, molecular dynamics simulations and immobilized enzyme catalysis experiments were employed to investigate the structural dynamics and catalytic activity of QU10-FTase. The effects of structure and activity regulation of QU10-FTase induced by different environments, including the immobilized Fe₃O₄ interface and solvent temperatures, were investigated. The results show that the catalytic activity of QU10-FTase is suppressed by the immobilized Fe₃O₄. The all-atom MD simulations revealed that the binding sites of QU10-FTase to the Fe₃O₄ interface are far away from the catalytic triad, but the structures of the catalytic sites are influenced by the interface binding via an allosteric mechanism. The relationship between the structure and catalytic activity of QU10-FTase under different temperatures further demonstrated the allosteric regulation in the FTase. Our results not only demonstrate the possibility of improving the enzyme activity of QU10-FTase to produce FOS but also provide new insights into the allosteric mechanisms of fructosyltransferase.