Quinohemoprotein alcohol dehydrogenases: structure, function, and physiology.
Quinohemoprotein alcohol dehydrogenases: structure, function, and physiology.
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DOI：
10.1016/j.abb.2004.03.037
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发表时间：
2004-08
影响因子：
3.9
通讯作者：
H. Toyama;F. Mathews;F. Mathews;O. Adachi;O. Adachi;K. Matsushita;K. Matsushita
中科院分区：
文献类型：
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作者：
H. Toyama;F. Mathews;F. Mathews;O. Adachi;O. Adachi;K. Matsushita;K. Matsushita
以吡咯并喹啉醌（PQQ）为辅基的醌（血红素）蛋白醇脱氢酶（ADH）分为3类，I型、II型和III型。I型ADH是具有PQQ作为唯一辅基的简单醌蛋白，而II型和III型ADH是在催化多肽中具有血红素c以及PQQ的醌血红素蛋白。II型ADH是一种可溶性周质酶，广泛分布于变形菌门，如假单胞菌属、罗尔斯通氏菌属、丛毛单胞菌属等。相反，III型ADH是一种膜结合酶，仅在醋酸菌中作用于周质表面。它由三个亚基组成，包括醌血红素蛋白催化亚基、三血红素细胞色素c亚基和功能未知的第三亚基。所有的醌（血红素）蛋白ADH的催化亚基有一个共同的结构基序，一个醌蛋白特异性的超桶结构域，其中PQQ深深地嵌入在中心。此外，在II型和III型ADH中，该亚基含有独特的血红素C结构域。各种II型ADH各自具有独特的底物特异性，接受各种各样的醇，如在最近的X射线晶体学分析的基础上讨论的。电子转移内的II型和III型ADH的分子内反应从PQQ血红素c和血红素血红素，并在分子间反应与天青和泛醌，分别进行了讨论。独特的生理功能的两种类型的quinohemoprotein ADH进行了讨论。
Quino(hemo)protein alcohol dehydrogenases (ADH) that have pyrroloquinoline quinone (PQQ) as the prosthetic group are classified into 3 groups, types I, II, and III. Type I ADH is a simple quinoprotein having PQQ as the only prosthetic group, while type II and type III ADHs are quinohemoprotein having heme c as well as PQQ in the catalytic polypeptide. Type II ADH is a soluble periplasmic enzyme and is widely distributed in Proteobacteria such as Pseudomonas, Ralstonia, Comamonas, etc. In contrast, type III ADH is a membrane-bound enzyme working on the periplasmic surface solely in acetic acid bacteria. It consists of three subunits that comprise a quinohemoprotein catalytic subunit, a triheme cytochrome c subunit, and a third subunit of unknown function. The catalytic subunits of all the quino(hemo)protein ADHs have a common structural motif, a quinoprotein-specific superbarrel domain, where PQQ is deeply embedded in the center. In addition, in the type II and type III ADHs this subunit contains a unique heme c domain. Various type II ADHs each have a unique substrate specificity, accepting a wide variety of alcohols, as is discussed on the basis of recent X-ray crystallographic analyses. Electron transfer within both type II and III ADHs is discussed in terms of the intramolecular reaction from PQQ to heme c and also from heme to heme, and in terms of the intermolecular reaction with azurin and ubiquinone, respectively. Unique physiological functions of both types of quinohemoprotein ADHs are also discussed.