铜型亚硝酸还原酶的电子传递模式及催化机理研究进展

The Progress on Electron Transport Pathway and Catalytic Mechanism of Copper-containing Nitrite Reductase

摘要:

亚硝酸还原酶(NiRs)是反硝化过程中的关键作用酶, 它使NO2- 转变成NO, 减轻了水体中的氮污染。根据辅基的不同, NiRs分为血红素cd1型亚硝酸还原酶(cd1-NiRs)和铜型亚硝酸还原酶(Cu-NiRs)两种。Cu-NiRs呈三聚体结构, 每个单体都含有两种类型的铜原子, 它们在酶催化过程中起着传递电子的重要作用。在催化过程中, Cu-NiRs中部分残基的结构变化有利于催化反应的进行。此文结合Cu-NiRs的最新研究成果, 从整体上对其结构特点、电子传递过程及催化机理等研究作了系统地阐述。

Abstract:

Nitrite reductases (NiRs) are the key enzymes in the denitrification pathway of the nitrogen cycle. By the catalysis of NiRs, the nitrites are turned into nitric oxides and the nitrogen pollution is decreased in water body. NiRs are divided into two different types based on their prosthetic groups, namely heme-containing nitrite reductases (cd1-NiRs) and Copper-containing nitrite reductases (Cu-NiRs). As all know, Cu-NiRs have trimeric structures, in their each monomer, there exist two types of Cu centers that play pivotal roles as the components of electron transfer pathway in the process of catalysis. Furthermore, some residues alteration of Cu-NiRs would contribute to the catalytic reaction. In this review, the latest progresses about the construction features, the process of electron transfer and catalytic mechanism of Cu-NiRs were discussed.