Analysis of active sites for N2 and H^+ reduction on FeMo-cofactor of nitrogenase |
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作者姓名: | GUAN Feng ZHAO DeHua PAN Miao JIANG Wei LI Jilun |
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作者单位: | State Key Laboratory for Agrobiotechnology and Department of Microbiology & Immunology, China Agricultural University, Beijing100094, China |
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基金项目: | Supported by National Key Basic Research Development Program of China (Grant No. 001CB 108904) |
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摘 要: | Dinitrogen (N2) and proton (H ),which act as physiological substrates of nitrogenase,are reduced on FeMo-co of the MoFe protein. However,researchers have different opinions about their exact reduction sites. Nitrogenases were purified from the wild type (WT) and five mutants of Azotobacter vinelandii (Av),including Qα191K,Hα195Q,nifV-,Qα191K/nifV- and Hα195Q/nifV-; and the activities of these en-zymes for N2 and H reduction were analyzed. Our results suggest that the Fe2 and Fe6,atoms closed to the central sulfur atom (S2B) within FeMo-co,are sites for N2 binding and reduction and the Mo atom of FeMo-co is the site for H reduction. Combining these data with further bioinformatical analysis,we propose that two parallel electron channels may exist between the 8Fe7S cluster and FeMo-co.
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关 键 词: | 固氮酶 固氮菌 双氮质子还原 电子转移路径 |
收稿时间: | 16 March 2007 |
修稿时间: | 2007-03-16 |
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