论文部分内容阅读
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.
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.