Mechanism of Biogenesis and Catalytic Function of Peptidyl Built-in Quinone Cofactors

肽基内置辅因子是通过同源酶蛋白的翻译后修饰产生的，不像通常的辅因子，其主要是由水溶性维生素生物合成的。在这项研究中，我们专注于两个内置的醌辅因子，铜胺氧化酶和醌血红素蛋白胺脱氢酶（QHNDH），分别含有topa醌（TPQ）和半胱氨酸醌（CTQ），。对于铜胺氧化酶的反应机理，已经证明前一个还原半反应伴随着TPQ的构象变化。另一方面，已发现两种编码接近QHNDH基因的蛋白质，[Fe-S]-簇和S-腺苷甲硫氨酸结合蛋白和枯草杆菌蛋白酶样蛋白酶，对QHNDH生物发生起重要作用。

Peptidyl built-in cofactors are produced by posttranslational modification of the cognate enzyme proteins, unlike ordinary cofactors which are mostly bio-synthesized from water soluble vitamins. In this study, we focused on two built-in quinone cofactor-containing enzymes, copper amine oxidase and quinohemoprotein amine dehydrogenase (QHNDH) that contain topa quinone (TPQ) and cysteine tryptophyl quinone (CTQ), respectively. For the reaction mechanism of copper amine oxidase, it has been demonstrated that the former reductive half-reaction is accompanied with the conformational change of TPQ. On the other hand, two proteins encoded close to the QHNDH genes, an [Fe-S]-cluster and S-adenosylmethionine-binding protein and a subtilisin-like protease, have been found to play essential roles for QHNDH biogenesis.