缺失nif Z的棕色固氮菌突变种钼铁蛋白的特性和结晶  

Characteristics and Crystallization of Nitrogenase MoFe Protein from a nif Z Deleted Stain of Azotobacter vinelandii

作　　者：汪道涌[1] 黄巨富[1] 钟泽璞[1] 李佳格 王耀萍[2] 汪志平[3] 

机构地区：[1]中国科学院植物研究所,北京100093 [2]中国科学院生物物理研究所,北京100101 [3]浙江大学核农学研究所,杭州310029

出　　处：《Acta Botanica Sinica》1999年第1期71-74,共4页Acta Botanica Sinica（植物学报：英文版）

基　　金：国家攀登项目;空间计划资助

摘　　要：从棕色固氮菌（Ａｚｏｔｏｂａｃｔｅｒ　ｖｉｎｅｌａｎｄｉｉ）缺失ｎｉｆＺ突变种中提纯得到的Δｎｉｆ　ＺＭｏＦｅ蛋白达到ＳＤＳ凝胶电泳纯。每个△ｎｆｉ　ＺＭｏＦｅ蛋白分子含１．５个Ｍｏ和１５．９个Ｆｅ原子，它的Ｆｅ和Ｍｏ比值低于野生型固氮菌ＭｏＦｅ蛋白的Ｆｅ和Ｍｏ比值，而它的Ｃ２Ｈ２、Ｈ＋还原活性及其比率（Ｃ２Ｈ４／Ｈ２（Ａｒ））分别为野生型ＭｏＦｅ蛋白的１６．６％、２１．７％和７７．２％。在与野生型ＭｏＦｅ蛋白结晶条件略有不同的情况下，所得的Δｎｉｆ　Ｚ　ＭｏＦｅ蛋白晶体为深棕色的斜四棱柱体晶体。表明ｎｉｆＺ的缺失可能使突变种ＭｏＦｅ蛋白中的Ｐ－ｃｌｕｓｔｅｒ或数目减少或结构发生变化，从而引起该蛋白的结构和功能发生明显改变。nif Z MoFe protein purified from a nif Z deleted strain of Antobacter vinelandii (DJ194) wasshown to be pure by SDS-Polyacrylamide gel electrophoresis. The protein contained 1. 5 Mo atoms and 15. 9 Featoms per molecule, the ratio of Fe to Mo was lower than that of the MoFe protein purified from the wild typestrain of A. vinelandii; and C2H2, H+ -reduction activity and their ratio (C2h4/H2 (Ar) ) were 16. 6%,21 .7% and 77 .2% of those of the wild type MoFe protein, respechvely. Under a somewhat different condi- tion from that for the crystallization of the wild type MoFe protein dark brown rhombohaedron crystals of nif ZMoFe protein were obtained. It indicated that the deletion of the nif Z resulted in the decrease of number or change in the structure of P-cluster in the mutant MoFe protein, which caused the significant structured and function of change of the protein.

关 键 词：棕色固氮菌 突变种 结构 功能 结晶 钼铁蛋白 

分 类 号：Q939.113[生物学—微生物学] Q936