Kalhor Hamid R, Piraman Zeinab, Fathali Yasaman
Biochemistry and Chemical Biology Research Laboratory, Department of Chemistry, Sharif University of Technology, Tehran, Iran.
iScience. 2023 Sep 1;26(10):107807. doi: 10.1016/j.isci.2023.107807. eCollection 2023 Oct 20.
Hen egg white lysozyme (HEWL) was exploited for the synthesis of β-amino carbonyl compounds through a direct and three-component Mannich reaction in aqueous, confirming high chemoselectivity toward imine. In order to further extend the applications of the enzyme, HEWL was encapsulated using a metal-organic framework (MOF). The reactivity, stereoselectivity, and reusability of the encapsulated enzyme were investigated. The reaction was significantly enhanced as compared to the non-encapsulated enzyme. A mutated version of the enzyme, containing Asp52Ala (D52A), lacking important catalytical residue, has lost the bacterial site activity against (. ) while the D52A variant displayed an increased rate of the Mannich reaction, indicating a different catalytical residue involved in the promiscuous reaction. Based on site-directed mutagenesis, molecular docking, and molecular dynamic studies, it was proposed that π-stacking, H-bond interactions, and the presence of water in the active site may play crucial roles in the mechanism of the reaction.
利用鸡蛋清溶菌酶（HEWL）通过直接的三组分曼尼希反应在水溶液中合成β-氨基羰基化合物，证实了对亚胺具有高化学选择性。为了进一步扩展该酶的应用，使用金属有机框架（MOF）对HEWL进行了封装。研究了封装酶的反应性、立体选择性和可重复使用性。与未封装的酶相比，反应显著增强。该酶的一个突变版本，含有Asp52Ala（D52A），缺少重要的催化残基，已失去对（.）的细菌位点活性，而D52A变体显示曼尼希反应速率增加，表明在杂乱反应中涉及不同的催化残基。基于定点诱变、分子对接和分子动力学研究，有人提出π-堆积、氢键相互作用以及活性位点中水分子的存在可能在反应机制中起关键作用。
