文献类型：期刊文献

英文题名：Proximal-to-distal molecular engineering of a halide methyltransferase for green synthesis of S-adenosyl-ethionine

作者：Zhang, Shi-Yu[1];Yang, Jun-Yi[1];Yan, Yang[1];Kang, Li-Xin[2];Li, Ai-Tao[2];Xu, Jian-He[1];Zheng, Gao-Wei[1];Chen, Qi[1]

机构：[1]East China Univ Sci & Technol, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China; East China Univ Sci & Technol, Shanghai Collaborat Innovat Ctr Biomfg, Shanghai 200237, Peoples R China;[2]Hubei Univ, Sch Life Sci, State Key Lab Biocatalysis & Enzyme Engn, Wuhan 430062, Peoples R China

年份：2026

卷号：588

外文期刊名：MOLECULAR CATALYSIS

收录：;EI(收录号：20254519442529);WOS:【SCI-EXPANDED(收录号:WOS:001603651400001)】；

基金：This work was financially supported by the Science and Technology Commission of Shanghai Municipality (25ZR1401078, 25HC2810400, 24HC2810300 and 23HC1400200) , the Open Funding Project of the State Key Laboratory of Biocatalysis and Enzyme Engineering (SKLBEE20220013) .

语种：英文

外文关键词：Halide methyltransferase; Proximal-to-distal molecular engineering; S -adenosyl-ethionine; Ethyl vanillin; Biocatalysis

摘要：Halide methyltransferases (HMTs) can efficiently catalyze the biosynthesis of S-adenosyl methionine (SAM) using natural substrates like methyl iodide or environmentally friendly alternatives such as methyl p-toluene sulfonate (MeOTs). Leveraging their broad substrate promiscuity, HMTs can also accommodate long-chain alkyl iodides and sulfonate esters, thereby facilitating the enzymatic production of structurally diverse SAM analogues. To address the limitations of existing S-adenosyl-ethionine (SAE) synthesis routes that depend on toxic alkyl halides like ethyl iodide, we developed a sustainable enzymatic strategy using ethyl p-toluene sulfonate (EtOTs) as the ethyl donor. Through a proximal-to-distal molecular engineering strategy, we systematically engineered wildtype Aspergillus clavatus halide methyltransferase (AcHMT) to enhance its catalytic properties. Following multiple rounds of semi-rational design, the mutant AcHMTM4 exhibited a 6.0-fold increase in specific activity toward EtOTs compare to the wild-type, reaching 0.30 mU mg-1, which represents the highest catalytic efficiency reported to date for this substrate. Molecular dynamics simulations subsequently revealed the structural mechanism of the improved catalytic activity. Biosynthesis of ethyl vanillin was achieved through a designed dual-enzyme cascade reaction. This work provides a universal strategy for engineering HMT to utilize sulfonate ester substrates, and an efficient biocatalyst for green synthesis of SAE for further ethyl modification of functional molecules.