Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, People's Republic of China.
Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, Anhui, People's Republic of China.
IUBMB Life. 2019 Mar;71(3):330-339. doi: 10.1002/iub.1977. Epub 2018 Nov 30.
Catechol-O-methyltransferase (COMT ) catalyzes the transfer of a methyl group from S-adenosylmethionine (SAM) to various catechol substrates. COMTs play vital roles in physiological processes in animals, plants, and fungi, as well as bacteria, and have essential application values in industry. spCOMT is a probable COMT from Schizosaccharomyces pombe. It has an extraordinary intracellular distribution different from other homologs and would thus be predicted to perform a distinct physiological function. In this report, recombinant spCOMT was purified and kinetically characterized for the first time. The enzymology assays indicate that spCOMT is a metal-dependent enzyme and belongs to class I OMTs. In addition, the crystal structures of apo-spCOMT and SAM-complexed spCOMT were also presented, revealing that spCOMT possesses a conserved SAM-binding site and Mg pocket, but a distinct substrate pocket was not present in homologs. The mutagenesis ITC analysis revealed the SAM recognition characteristics of spCOMT. Based on all of the above findings, we speculated about the putative substrates' characteristics and the substrate recognition mechanisms of spCOMT. This work will help in elucidating the physiological functions of spCOMT in S. pombe. © 2018 IUBMB Life, 71(3):330-339, 2019.
儿茶酚-O-甲基转移酶（COMT）催化 S-腺苷甲硫氨酸（SAM）向各种儿茶酚底物转移甲基。COMT 在动物、植物和真菌以及细菌的生理过程中发挥着重要作用，在工业中有重要的应用价值。spCOMT 是裂殖酵母中的一种可能的 COMT。它具有独特的细胞内分布，与其他同源物不同，因此预计具有独特的生理功能。在本报告中，首次对重组 spCOMT 进行了纯化和动力学表征。酶学测定表明，spCOMT 是一种依赖金属的酶，属于 I 类 OMTs。此外，还呈现了 apo-spCOMT 和 SAM 复合 spCOMT 的晶体结构，揭示了 spCOMT 具有保守的 SAM 结合位点和 Mg 口袋，但在同源物中不存在独特的底物口袋。ITC 突变分析揭示了 spCOMT 的 SAM 识别特征。基于所有这些发现，我们推测了 spCOMT 的假定底物特征和底物识别机制。这项工作将有助于阐明 spCOMT 在裂殖酵母中的生理功能。© 2018 IUBMB Life，71（3）：330-339，2019。
