Anthony C, Ghosh M
Division of Biochemistry and Molecular Biology, School of Biological Sciences, University of Southampton, U.K.
Prog Biophys Mol Biol. 1998;69(1):1-21. doi: 10.1016/s0079-6107(97)00020-5.
Bacterial methanol and glucose dehydrogenases containing a novel type of prosthetic group, subsequently identified as pyrrolo-quinoline quinone (PQQ), were first described about 30 years ago. Quinoproteins were originally defined as proteins containing PQQ but this definition has since been broadened to include those proteins containing other types of quinone-containing prosthetic groups, and the X-ray structures of representatives of each type of quinoprotein have recently been published. This review is mainly concerned with the structure and function of the PQQ-containing methanol dehydrogenase, whose structure has been determined at high resolution, and related proteins. Their basic structure consists of a 'propeller' fold superbarrel made up of 8-sheet 'propeller blades' which are held together by novel tryptophan-docking motifs. In methanol dehydrogenase the PQQ in the active site is coordinated to a Ca2+ ion and is maintained in position by a stacked tryptophan and a novel 8-membered ring structure made up of a disulphide bridge between adjacent cysteine residues. This review describes these features and discusses them in relation to previously proposed mechanisms for this enzyme.
大约30年前首次描述了含有一种新型辅基的细菌甲醇脱氢酶和葡萄糖脱氢酶，该辅基后来被鉴定为吡咯并喹啉醌（PQQ）。醌蛋白最初被定义为含有PQQ的蛋白质，但此后该定义已扩大到包括那些含有其他类型含醌辅基的蛋白质，并且最近已经发表了每种类型醌蛋白代表的X射线结构。本综述主要关注含PQQ的甲醇脱氢酶的结构和功能，其结构已在高分辨率下确定，以及相关蛋白质。它们的基本结构由一个“螺旋桨”折叠超桶组成，该超桶由8个片层的“螺旋桨叶片”组成，这些叶片通过新型色氨酸对接基序结合在一起。在甲醇脱氢酶中，活性位点的PQQ与Ca2+离子配位，并通过一个堆叠的色氨酸和一个由相邻半胱氨酸残基之间的二硫键组成的新型八元环结构保持在该位置。本综述描述了这些特征，并结合先前提出的该酶的作用机制进行了讨论。
