Optimization of the process and kinetic mechanism of ginsenoside Rb1 conversion by β-glucanase

Ginsenoside F2 has multiple biological effects, such as cardiovascular protection, antioxidant. However, ginsenoside F2 is extremely low in natural ginseng plants; it can be obtained by deglycosylation of ginsenoside Rb1. In this paper, high-performance liquid chromatography, fourier transform infrared spectroscopy, ultraviolet spectroscopy, and fluorescence spectroscopy were used to study the molecular mechanism of β-glucanase in the conversion of rare ginsenoside F2. The ability of β-glucanase to convert ginsenoside Rb1 into ginsenoside F2 was examined. Molecular dynamics simulation and molecular docking were used to identify the putative binding site of β-glucanase and ginsenoside Rb1 as well as the optimal binding conformation. The results showed that β-glucanase and ginsenosides Rb1 and Rd can spontaneously interact with each other. the dynamic binding process of the active site during the conversion of ginsenoside Rb1 to F2 by β-glucanase was verified by spectroscopic experiments, and the molecular basis of the conformational relationship was elucidated and validated by molecular simulations. This study established a multi-scale research approach by integrating spectroscopic analysis with molecular simulation. This methodology not only optimized the process for converting Rb1 to F2 by β-glucanase but also elucidated the structural basis of its regioselectivity at the molecular level. This work not only provides a paradigm for elucidating the transformation mechanism of glycosidases but also establishes an efficient route for producing precious rare ginsenosides.