Purification and Characterization of Cr-containing Nitrogenase Component Ⅰ  

含铬固氮酶组分Ⅰ蛋白的纯化和特性(英文)

作　　者：黄巨富[1] 董志刚[1] 张华峰[1] 吕玉兵[1] 赵颖[1] 汪志平[1] 

机构地区：[1]中国科学院植物研究所,北京100093

出　　处：《Acta Botanica Sinica》2002年第3期297-300,共4页Acta Botanica Sinica（植物学报：英文版）

基　　金：国家自然科学基金 ( 2 97710 33,0 0 1CB10 89)~~

摘　　要：A mutant UW 3, which is unable to fix N 2 in the presence of Mo (Nif -) but can undergo phenotypic reversal to Nif + under Mo_deficient conditions, was able to grow in Cr_containing but Mo_ and NH 3_deficient medium. A partly purified nitrogenase component Ⅰ protein obtained from UW 3 grown on the Cr_containing medium was shown to contain Fe and Cr (atom ratio of Fe to Cr and Mo to Cr: 11.60 and 0.41) and to have 70% of the C 2H 2_ and H +_reduction activity of MoFe protein from the wild_type strain of Azotobacter vinelandii Lipmann. The Cr_containing protein was different in subunit composition from that of MnFe protein purified from the mutant strain grown in the presence of Mn, but similar to that of MoFe protein, that is, it was a tetramer composed of two different subunits (α 2β 2). The preliminary results indicated that the Cr_containing protein might be a nitrogenase component Ⅰ protein.在含Mo固氮培养基中不能生长而在无Mo条件下可固氮生长的固氮菌 (AzotobactervinelandiiLipmann)突变种UW3 ,能在无Mo而含Cr的无氮培养基中生长。从菌体中分离得到的部分纯固氮酶组分Ⅰ蛋白含有Cr和Fe原子 (Fe/Mo/Cr为 11.6 0∶0 .41∶1.0 0 ) ,并能表达相当于棕色固氮菌野生型固氮菌MoFe蛋白对乙炔和质子还原的 70 %的活性。与从Mn中生长的UW3 菌体中所提取纯化的MnFe蛋白不同 ,这种含铬蛋白与MoFe蛋白 (α2 β2 )一样 ,是由两种亚基组成的四聚体。初步结果表明 ,这种含Cr蛋白可能是一种固氮酶组分Ⅰ蛋白。

关 键 词：NITROGENASE Cr_containing protein mutant UW  3 

分 类 号：Q946.1[生物学—植物学]