Xie Zhihong, Dou Yuetang, Ping Shuzheng, Chen Ming, Wang Guoying, Elmerich Claudine, Lin Min
Biotechnology Research Institute, CAAS, Beijing, PR China.
Biology College, China Agricultural University, Beijing, PR China.
Microbiology (Reading). 2006 Dec;152(Pt 12):3535-3542. doi: 10.1099/mic.0.29171-0.
Pseudomonas stutzeri strain A1501 isolated from rice fixes nitrogen under microaerobic conditions in the free-living state. This paper describes the properties of nifL and nifA mutants as well as the physical interaction between NifL and NifA proteins. A nifL mutant strain that carried a mutation non-polar on nifA expression retained nitrogenase activity. Complementation with a plasmid containing only nifL led to a decrease in nitrogenase activity in both the wild-type and the nifL mutant, suggesting that NifL acts as an antiactivator of NifA activity. Using the yeast two-hybrid system and purified protein domains of NifA and NifL, an interaction was shown between the C-terminal domain of NifL and the central domain of NifA, suggesting that NifL antiactivator activity is mediated by direct protein interaction with NifA.
从水稻中分离出的斯氏假单胞菌菌株A1501在自由生活状态下于微需氧条件下固氮。本文描述了nifL和nifA突变体的特性以及NifL和NifA蛋白之间的物理相互作用。携带对nifA表达无极性突变的nifL突变体菌株保留了固氮酶活性。用仅含有nifL的质粒进行互补导致野生型和nifL突变体中的固氮酶活性均降低，这表明NifL作为NifA活性的反激活因子发挥作用。使用酵母双杂交系统以及纯化的NifA和NifL蛋白结构域，显示NifL的C末端结构域与NifA的中央结构域之间存在相互作用，这表明NifL反激活因子活性是由与NifA的直接蛋白质相互作用介导的。
