Functional and structural characterization of a novel catechol-O -methyltransferase from Schizosaccharomyces pombe
Functional and structural characterization of a novel catechol-O -methyltransferase from Schizosaccharomyces pombe
复制标题
裂殖酵母新型儿茶酚-O-甲基转移酶的功能和结构表征
作者：
Qing Wang;Maikun Teng;Xu Li
儿茶酚-O-甲基转移酶（COMT 1）催化甲基从S-腺苷甲硫氨酸（SAM）转移到各种儿茶酚底物。COMT在动物、植物、真菌和细菌的生理过程中起着重要作用，在工业上具有重要的应用价值。它具有不同于其他同系物的非凡的细胞内分布，因此可以预测其具有独特的生理功能。本文首次对重组spCOMT进行了纯化和动力学研究。酶学分析表明，spCOMT是一种金属依赖性酶，属于I类OMT。此外，还提供了apo-spCOMT和SAM-复合物spCOMT的晶体结构，揭示spCOMT具有保守的SAM-结合位点和Mg 2+口袋，但在同系物中不存在明显的底物口袋。突变ITC分析揭示了spCOMT的SAM识别特性。基于以上研究结果，我们推测了spCOMT的底物特征和底物识别机制。本研究为进一步阐明spCOMT在粟酒裂殖酵母中的生理功能奠定了基础。© 2018 IUBMB Life，71（3）：330-339，2019
Catechol‐O‐methyltransferase (COMT1) 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 fromSchizosaccharomyces 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, recombinantspCOMT was purified and kinetically characterized for the first time. The enzymology assays indicate thatspCOMT is a metal‐dependent enzyme and belongs to class I OMTs. In addition, the crystal structures of apo‐spCOMT and SAM‐complexedspCOMT were also presented, revealing thatspCOMT possesses a conserved SAM‐binding site and Mg2+pocket, but a distinct substrate pocket was not present in homologs. The mutagenesis ITC analysis revealed the SAM recognition characteristics ofspCOMT. Based on all of the above findings, we speculated about the putative substrates’ characteristics and the substrate recognition mechanisms ofspCOMT. This work will help in elucidating the physiological functions ofspCOMT inS. pombe. © 2018 IUBMB Life, 71(3):330–339, 2019