Protection of nitrogenase in Azotobacter vinelandii.
نویسندگان
چکیده
The site or sites that protect nitrogenase from O(2) inactivation in vivo are sensitive to sodium azide or 2,4-dinitrophenol. Both components of nitrogenase can be synthesized when oxidative phosphorylation is disrupted.
منابع مشابه
Noncoupled NADH:ubiquinone oxidoreductase of Azotobacter vinelandii is required for diazotrophic growth at high oxygen concentrations.
The gene encoding the noncoupled NADH:ubiquinone oxidoreductase (NDH II) from Azotobacter vinelandii was cloned, sequenced, and used to construct an NDH II-deficient mutant strain. Compared to the wild type, this strain showed a marked decrease in respiratory activity. It was unable to grow diazotrophically at high aeration, while it was fully capable of growth at low aeration or in the presenc...
متن کاملRespiratory Protection of Nitrogenase Activity in <Emphasis Type="Italic">Azotobacter vinelandii</Emphasis>Roles of the Terminal Oxidases
Nitrogen fixation by aerobic prokaryotes appears paradoxical: the nitrogen-fixing enzymes— nitrogenases—are notoriously oxygen-labile, yet many bacteria fix nitrogen aerobically. This review summarises the evidence that cytochrome bd, a terminal oxidase unrelated to the mitochondrial and many other bacterial oxidases, plays a crucial role in aerotolerant nitrogen fixation in Azotobacter vinelan...
متن کاملEffect of oxygen on formation and structure of Azotobacter vinelandii alginate and its role in protecting nitrogenase.
The activity of nitrogenase in the nitrogen-fixing bacterium Azotobacter vinelandii grown diazotrophically under aerobic conditions is generally considered to be protected against O(2) by a high respiration rate. In this work, we have shown that a high rate of respiration is not the prevailing mechanism for nitrogenase protection in A. vinelandii grown in phosphate-limited nitrogen-free chemost...
متن کاملNature of oxygen inhibition of nitrogenase from Azotobacter vinelandii.
The reduction of nitrogen, acetylene, azide, and cyanide at various oxygen concentrations by nitrogenase from Azotobacter vinelandii was measured with a well-defined system. Oxygen inhibited the reduction of each substrate uncompetitively. The inhibition constants (K(i)) were 0.014, 0.023, 0.008, and 0.003 atm of oxygen for reduction of nitrogen, acetylene, azide, and cyanide, respectively. The...
متن کاملRegulation of nitrogen fixation in Azotobacter vinelandii OP and in an apparently partially constitutive mutant.
Methylamine and 2-methylalanine appeared to act as co-repressors of nitrogenase in Azotobacter vinelandii OP. They inhibited the growth of this organism on molecular nitrogen but not on nitrate, ammonia, or Casamino Acids; they prevented the formation of nitrogenase by cells transferred from repression to induction conditions; and they did not inhibit the activity of nitrogenase in vitro. A mut...
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ورودعنوان ژورنال:
- Journal of bacteriology
دوره 115 1 شماره
صفحات -
تاریخ انتشار 1973