Department of Life Science and Biotechnology, Kansai University, Suita, Osaka, Japan.
Biosci Biotechnol Biochem. 2021 Jun 24;85(7):1675-1685. doi: 10.1093/bbb/zbab079.
The fungus Exophiala jeanselmei strain KUFI-6N produces a unique cycloalkanone monooxygenase (ExCAMO) that displays an uncommon substrate spectrum of Baeyer-Villiger oxidation of 4-10-membered ring ketones. In this study, we aimed to identify and sequence the gene encoding ExCAMO from KUFI-6N and overexpress the gene in Escherichia coli. We found that the primary structure of ExCAMO is most closely related to the cycloalkanone monooxygenase from Cylindrocarpon radicicola ATCC 11011, with 54.2% amino acid identity. ExCAMO was functionally expressed in E. coli and its substrate spectrum and kinetic parameters were investigated. Substrate profiling indicated that ExCAMO is unusual among known Baeyer-Villiger monooxygenases owing to its ability to accept a variety of substrates, including C4-C12 membered ring ketones. ExCAMO has high affinity and catalytic efficiency toward cycloalkanones, the highest being toward cyclohexanone. Five other genes encoding Baeyer-Villiger monooxygenases were also cloned and expressed in E. coli.
青霉属真菌菌株 KUFI-6N 产生一种独特的环烷酮单加氧酶（ExCAMO），它对 Baeyer-Villiger 氧化 4-10 元环酮显示出不常见的底物谱。在本研究中，我们旨在从 KUFI-6N 中鉴定和测序编码 ExCAMO 的基因，并在大肠杆菌中过表达该基因。我们发现 ExCAMO 的一级结构与来自旋孢腔菌的环烷酮单加氧酶最接近，氨基酸同一性为 54.2%。ExCAMO 在大肠杆菌中功能表达，并对其底物谱和动力学参数进行了研究。底物谱分析表明，ExCAMO 是一种不同寻常的 Baeyer-Villiger 单加氧酶，因为它能够接受多种底物，包括 C4-C12 元环酮。ExCAMO 对环烷酮具有高亲和力和催化效率，对环己酮的亲和力和催化效率最高。还克隆并在大肠杆菌中表达了另外五个编码 Baeyer-Villiger 单加氧酶的基因。
