棕色固氮菌缺失nifZ基因的突变种固氮酶MoFe蛋白的纯化和性质  

PURIFICATION AND PROPERTIES OF NITROGENASE MoFe PROTEIN FROM A NIF Z DELETION STRAIN OF AZOTOBACTER VINELANDII

作　　者：钟泽璞[1] 胡长征[1] 王继伟[1] 黄巨富[1] 骆爱玲[1] 李佳格 

机构地区：[1]中国科学院植物研究所,北京100093

出　　处：《Acta Botanica Sinica》1996年第8期605-611,共7页Acta Botanica Sinica（植物学报：英文版）

基　　金：国家攀登项目;国家自然科学基金

摘　　要：采用 52℃下加热 6 min,后经 DEAE- 52、Sephacryls S- 2 0 0和 Q- Sepharose等柱层析方法 ,分离纯化了棕色固氮菌 (Azotobacter vinelandii)缺失 nif Z基因突变种固氮酶 Mo Fe(Δnif Z Mo Fe)蛋白 ,其纯度达到电泳纯。Δnif Z Mo Fe蛋白的固氮活性为 2 83nmol C2 H2 还原 / (min·mg蛋白 ) ,远低于野生种 Mo Fe蛋白。Δnif Z Mo Fe蛋白对氧更敏感 ;热稳定性略低于野生种。Δnif Z Mo Fe蛋白的可见光吸收光谱与野生种 Mo Fe蛋白极为相似。其圆二色谱和磁圆二色谱在 450～ 550 nm与野生种 Mo Fe蛋白显著不同 ,表明其 P- cluster及其周围环境与野生种 Mo Fe蛋白有所差异。这亦可能是造成缺失 nif Z突变种 Mo Fe蛋白固氮活性低的原因。The MoFe protein of the nif Z deletion strain (Δnif Z MoFe protein) of Azotobacter vinelandii designated DJ 194 was purified and some properties were studied.The cell free extract of DJ 194 was more sensitive to O 2 and heat than the wild type extract.The specific activity of the purified DJ 194 protein was 283 nmol C 2H 2 reduced/(min·mg protein),which was much lower than that of purified wild type A. vinelandii MoFe protein.The Δnif Z MoFe protein exhibited a visible similar absorption spectra as the wild type MoFe protein,yet showed significant difference in CD and MCD spectra at the region about 450 mm comparing with the spectral property of the wild type MoFe protein.This seems to indicate that the P cluster of the Δnif Z MoFe protein was modified,which might be the cause of the low activity of the DJ 194 MoFe protein.

关 键 词：棕色固氮菌 MoFe蛋白 固氮酶 

分 类 号：Q939.113[生物学—微生物学]