Structural investigation of the cofactor-free chloroperoxidases
Structural investigation of the cofactor-free chloroperoxidases
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DOI：
10.1006/jmbi.1998.1802
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发表时间：
1998-06-19
影响因子：
5.6
通讯作者：
Hecht, HJ
中科院分区：
文献类型：
--
作者：
Hofmann, B;Tölzer, S;Hecht, HJ
来自金色链霉菌、变铅青链霉菌和荧光假单胞菌的无辅因子卤代过氧化物酶的结构已在1.9埃和1.5埃之间的分辨率下确定。与苯甲酸盐或丙酸盐复合的两种酶的结构确定了卤代过氧化物酶活性所需的有机酸的结合位点。基于这些配合物和非活性变体的结构，提出了以过氧酸和次卤酸为反应中间体的卤化反应的反应机理。结构的比较表明，一个特定的卤化物结合位点是不存在的酶，但疏水性有机化合物可能适合在优先位点卤化的活性位点口袋。(C)出版社：Academic Press Limited。
The structures of cofactor-free haloperoxidases from Streptomyces aureofaciens, Streptomyces lividans, and Pseudomonas fluorescens have been deter mined at resolutions between 1.9 Angstrom and 1.5 Angstrom. The structures of two enzymes complexed with benzoate or propionate identify the binding site for the organic acids which are required for the haloperoxidase activity. Based on these complexes and on the structure of an inactive variant, a reaction mechanism is proposed for the halogenation reaction with peroxoacid and hypohalous acid as reaction intermediates. Comparison of the structures suggests that a specific halide binding site is absent in the enzymes but that hydrophobic organic compounds may fit into the active site pocket for halogenation at preferential sites. (C) 1998 Academic Press Limited.