碳水化合物活性酶负责合成和降解各种碳水化合物中的糖苷键。果糖基转移酶代表这些酶的一个亚类,使用蔗糖作为底物以产生低聚果糖(FOS)和果聚糖聚合物。此类别主要包括蔗糖酶(LS,EC2.4.1.10),inulosuccrase(IS,EC2.4.1.9),和β-呋喃果糖苷酶(Ffase,EC3.2.1.26)。这三种酶具有相似的五叶β-螺旋桨折叠,并采用亲核试剂介导的端基体保留反应机制,过渡态稳定器,和一般的酸/碱。然而,他们展示了不同的产品概况,特征在于连锁特异性和分子质量分布的变化。因此,本文全面探讨了催化特性的最新进展,结构特征,反应机制,和左旋蔗糖酶的产品特异性,inulosurecrase,和β-呋喃果糖苷酶(缩写为LS,IS,还有Ffase,分别)。此外,它讨论了通过基于结构的设计来修改催化性能和产物特异性的潜力,这使得定制果聚糖和FOS的合理生产成为可能。
Carbohydrate-active enzymes are accountable for the synthesis and degradation of glycosidic bonds among diverse carbohydrates. Fructosyl-transferases represent a subclass of these enzymes, employing sucrose as a substrate to generate fructooligosaccharides (FOS) and fructan polymers. This category primarily includes levansucrase (LS, EC 2.4.1.10), inulosucrase (IS, EC 2.4.1.9), and β-fructofuranosidase (Ffase, EC 3.2.1.26). These three enzymes possess a similar five-bladed β-propeller fold and employ an anomer-retaining reaction mechanism mediated by nucleophiles, transition state stabilizers, and general acids/bases. However, they exhibit distinct product profiles, characterized by variations in linkage specificity and molecular mass distribution. Consequently, this article comprehensively explores recent advancements in the catalytic characteristics, structural features, reaction mechanisms, and product specificity of levansucrase, inulosucrase, and β-fructofuranosidase (abbreviated as LS, IS, and Ffase, respectively). Furthermore, it discusses the potential for modifying catalytic properties and product specificity through structure-based design, which enables the rational production of custom fructan and FOS.