Levan型低聚果糖(LFOS)具有显著的生物学活性,选择性地促进某些有益菌的生长。Levanase是生产LFOS的重要酶。在这项研究中,两种同工酶,外型和内型解聚酶,从枯草芽孢杆菌中分离出的HM7,表达,和特点。评价了两种同工型对果聚糖水解和动力学性质的协同作用,表明他们在左旋代谢中的合作,其中内-左旋酶催化限速步骤。此外,同源性模型和分子动力学模拟揭示了催化和果聚糖结合酶的关键氨基残基。发现两种同工型在活性位点具有不同的结合残基,表明酶特异性的重要性。最后,我们证明了内型左旋糖酶在LFOS合成中的潜力,使用一锅反应与左旋蔗糖酶。总的来说,这项研究缩小了在理解葡聚糖酶机理方面的知识差距,为食品科学和生物技术做出了重要贡献。
Levan-type fructooligosaccharides (LFOS) exhibit significant biological activities and selectively promote the growth of certain beneficial bacteria. Levanase is an important enzyme for LFOS production. In this study, two isoforms of levanases, exo- and endo-type depolymerizing enzymes, from Bacillus subtilis HM7 isolated from Dynastes hercules larvae excrement were cloned, expressed, and characterized. The synergistic effect on the levan hydrolysis and kinetic properties of both isoforms were evaluated, indicating their cooperation in levan metabolism, where the endo-levanase catalyzes a rate-limiting step. In addition, homology models and molecular dynamics simulations revealed the key amino residues of the enzymes for levan binding and catalysis. It was found that both isoforms possessed distinct binding residues in the active sites, suggesting the importance of the specificity of the enzymes. Finally, we demonstrated the potential of endo-type levanase in LFOS synthesis using a one-pot reaction with levansucrase. Overall, this study fills the knowledge gap in understanding levanase\'s mechanism, making an important contribution to the fields of food science and biotechnology.