Structure of cytochrome P450eryF: Substrate, inhibitors, and model compounds bound in the active site
Structure of cytochrome P450eryF: Substrate, inhibitors, and model compounds bound in the active site
复制标题
DOI：
10.1016/s0039-128x(96)00168-7
复制
发表时间：
1997-01-01
期刊：
影响因子：
2.7
通讯作者：
Poulos, TL
中科院分区：
文献类型：
--
作者：
CuppVickery, JR;Poulos, TL
我们对P450反应机制的理解来源于对细菌樟脑羟化酶P450 cam的研究。P450 cam被艾德认为是理解哺乳动物P450酶中偏离的结构-功能关系的模型，这还没有被证明是适合于X射线晶体学技术的。为了扩展和改进P450模型，我们解决了P450 eryF的结构，P450 eryF是一种参与红霉素生物合成的细胞色素P450。P450 eryF的整体结构与P450 cam相似，但不同之处在于几个α-螺旋的精确定位，这导致底物结合口袋的扩大。P450 eryF与P450 cam的不同之处还在于活性位点中高度保守的苏氨酸残基被丙氨酸取代。为了评估该丙氨酸残基的作用，检查了P450 eryF的两种突变形式和底物类似物。我们的研究结果表明，P450 eryF已经进化出一个活性位点，利用底物来协助催化。此外，P450 eryF的扩大的底物结合包使得P450 eryF能够结合某些类固醇化合物和基于吡咯的类固醇羟化酶抑制剂。已经获得了与抗真菌药物酮康唑络合的P450 eryF的晶体，并确定了高分辨率结构。(C)Elsevier Science Inc.出版。
Which of our understanding of P450 reaction mechanisms derives from studies on P450cam, a bacterial camphor hydroxylase. P450cam has sen ed as the model far understanding derailed structurelfunction relationships in mammalian P450 enzymes, which have not proved amenable to x-ray crystallographic techniques. To expand and improve the P450 model, we solved the structure of P450eryF, a cytochrome P450 involved in erythromycin biosynthesis. The overall structure of P450eryF is similar to that of P450cam, but differs in the exact positioning of several alpha-helices, which results in the enlargement of the substrate-binding pocket. P450eryF also differs from P450cam in having alanine in place of the highly conserved threonine residue in the active site. To assess the role of this alanine residue, two mutant forms of P450eryF and a substrate analog were examined. Our findings suggest that P450eryF has evolved an active site that utilizes the substrate to assist in catalysis. in addition, the Enlarged substrate binding packet of P450eryF enables P450eryF to bind certain steroid compounds and azole-based steroid hydroxylase inhibitors. Crystals have been obtained for P450eryF complexed with the antifungal drug ketoconazole, and the high-resolution structure has been determined. (C) 1997 by Elsevier Science Inc.