In crude cell-free extracts of Azotobacter chroococcum, nitrogenase was much less sensitive to irreversible inactivation by O2 than was the purified enzyme. When nitrogenase was partially purified by anaerobic discontinuous sucrose-density-gradient centrifugation, O2-tolerance was retained. This preparation was considerably enriched in four polypeptides, three of which were derived from the Mo-...

Peptidyl-prolyl cis/trans isomerases (PPIases) play a pivotal role in catalyzing the correct folding of many prokaryotic and eukaryotic proteins that are implicated in a variety of biological functions, ranging from cell cycle regulation to bacterial infection. The nif accessory protein NifM, which is essential for the biogenesis of a functional NifH component of nitrogenase, is a PPIase. To un...

Vela, Gerard R. (School of Aerospace Medicine, Brooks Air Force Base, Tex.), and Orville Wyss. Radiation resistance of soil Azotobacter. J. Bacteriol. 89:1280-1285. 1965.-Quantitative recovery of Azotobacter from soils subjected to gamma-radiation from a cobalt-60 source showed the soil populations to be much more highly resistant than isolates from such cultures grown on laboratory media. Even...

It has been reported (Gunter, 1954) that Mg++ prolongs the viability of various microorganisms suspended in potassium phosphate buffer, and that celLs of Azotobacter are singularly affected by MgSO4. It was previously observed (Goucher and Kocholaty, 1954) that MgSO4 is required for the oxidation of several organic compounds by whole cells of Azotobacter agile. Data presented in this communicat...

Biological N2 fixation, the reduction of N2 to NH 3 , is catalyzed by the enzyme nitrogenase . Fractionation studies of nitrogenases from a variety of organisms have shown that all are composed of two similar proteins, one contains Mo and Fe and is called the Mo-Fe protein and the other contains only Fe and is called the Fe protein . Recently homogeneous preparations of these proteins from Azot...

Biofertilizers are living microorganisms; they themselves are not source of nutrients but can help the plant in accessing the nutrient available in its surrounding environments (Suman et al., 2015). In general, commonly microbes used as biofertilizers may be Azotobacter, Azospirillum, Rhizobium as nitrogen fixing soil bacteria (Verma et al., 2013, 2014; Verma et al., 2015; Verma et al., 2016a);...

Vanadium K-edge X-ray-absorption spectra were collected for samples of thionine-oxidized, super-reduced (during enzyme turnover) and dithionite-reduced VFe-protein of the vanadium nitrogenase of Azotobacter chroococcum (Acl*). Both the e.x.a.f.s and the x.a.n.e.s. (X-ray-absorption near-edge structure) are consistent with the vanadium being present as part of a VFeS cluster; the environment of ...

Azotobacter vinelandii cell extracts reduced NAD and oxidized d-galactose to galactonate that subsequently was converted to 2-keto-3-deoxy-galactonate. Further metabolism of 2-keto-3-deoxy-galactonate required the presence of ATP and resulted in the formation of pyruvate and glyceraldehyde 3-P. Radiorespirometry indicated a preferential release of CO(2) at the first carbon position of the d-gal...

Cysts of Azotobacter vinelandii produced in chemical salts-agar supplemented with 0.1 to 1.0% yeast extract and 0.3% butanol (L. E. Jackson, M.S. Thesis, Univ. of Texas, Austin, 1961) were two to four times larger than cysts formed on nitrogen-free medium (Fig. 1 and 2). Microscopic studies of "giant" cysts transferred to nitrogenfree agar revealed that, prior to germination, the central body d...

Nitrogenase is an essential metalloenzyme that catalyzes the biological conversion of dinitrogen (N(2)) to ammonia (NH(3)). The vanadium (V)-nitrogenase is very similar to the "conventional" molybdenum (Mo)-nitrogenase, yet it holds unique properties of its own that may provide useful insights into the general mechanism of nitrogenase catalysis. So far, characterization of the vanadium iron (VF...