Riddle G D, Simonson J G, Hales B J, Braymer H D
J Bacteriol. 1982 Oct;152(1):72-80. doi: 10.1128/jb.152.1.72-80.1982.
Mutants of Azotobacter vinelandii ATCC 12837 were isolated which could fix N2 in the presence of high tungsten concentrations. The most studied of these mutants (WD2) grew well in N-free modified Burk broth containing 10 mM W, whereas the wild type would not grow in this medium. WD2 would also grow in Burk N-free broth at about the same rate as the wild type. WD2 in broth containing W exhibited 22% of the whole cell acetylene reduction activity of the wild type in broth containing Mo and showed a lowered affinity for acetylene. Two-dimensional gel electrophoresis experiments showed that N2-fixing cells of WD2 from broth containing W or Mo did not produce significant amounts of component I of native nitrogenase protein. Electron spin resonance spectra of whole cells and cell-free extracts of WD2 from broth containing W lacked any trace of the g = 3.6 resonance associated with FeMoCo.
分离出了维涅兰德固氮菌ATCC 12837的突变体，这些突变体能够在高钨浓度下固定氮气。其中研究最多的突变体（WD2）在含有10 mM钨的无氮改良伯克氏肉汤中生长良好，而野生型在这种培养基中无法生长。WD2在伯克氏无氮肉汤中的生长速度与野生型大致相同。含有钨的肉汤中的WD2表现出含有钼的肉汤中野生型全细胞乙炔还原活性的22%，并且对乙炔的亲和力降低。二维凝胶电泳实验表明，来自含有钨或钼的肉汤中的WD2的固氮细胞不会产生大量天然固氮酶蛋白的组分I。来自含有钨的肉汤中的WD2的全细胞和无细胞提取物的电子自旋共振光谱没有任何与铁钼辅因子相关的g = 3.6共振的痕迹。
