Nitrogenase Complex
نویسنده
چکیده
The nitrogenase complex carries out the fixation of nitrogen by reducing molecular dinitrogen (N2) to ammonium (NH4 1 ) and also reduces acetylene to ethylene. The two component proteins are dinitrogenase and dinitrogenase reductase. Although different metals can form the metal clusters contained in nitrogenase proteins, all nitrogenases have similar properties. The nitrogenase enzyme system is widely distributed among the Bacteria and the Archaea, with protein sequences highly conserved across the kingdoms.
منابع مشابه
Characterization of an oxygen-stable nitrogenase complex isolated from Azotobacter chroococcum.
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-...
متن کاملInteractions of heterologous nitrogenase components that generate catalytically inactive complexes.
A unique method is described for inhibiting nitrogenase. When Clostridium pasteurianum nitrogenase is assayed in the presence of the Mo-Fe protein of Azotobacter vinelandii, all the characteristic activities of nitrogenase are inhibited. C. pasteurianum nitrogenase is unaffected by the Fe protein of A. vinelandii. The Fe protein, but not the Mo-Fe protein of C. pasteurianum, inhibits A. vinelan...
متن کاملStructural Evidence for Asymmetrical Nucleotide Interactions in Nitrogenase
The roles of ATP hydrolysis in electron-transfer (ET) reactions of the nitrogenase catalytic cycle remain obscure. Here, we present a new structure of a nitrogenase complex crystallized with MgADP and MgAMPPCP, an ATP analogue. In this structure the two nucleotides are bound asymmetrically by the Fe-protein subunits connected to the two different MoFe-protein subunits. This binding mode suggest...
متن کاملNitrogenase: a nucleotide-dependent molecular switch.
INTRODUCTION .......................................... 235 PROPERTIES OF THE NITROGENASE PROTEINS ................... 237 Fe-Protein ............................................ 238 MoFe-Protein .......................................... 241 Species-Specific Variations in Nitrogenase Proteins ................... 245 GENETICS AND ASSEMBLY OF TIIE NITROGENASE PROTEINS ........ 246 MECHANISM OF N...
متن کاملThe Expression of a Third Nitrogenase in the Cyanobacterium Anabaena variabilis
Physiological experiments indicate that Anabaena variabilis can express either a Vor a Fe-nitrogenase in addition to the conventional, Mo-containing enzyme complex. The occur rence o f the Fe-nitrogenase in A. variabilis can also be concluded from D N A -D N A hybridiza tion experiments using cloned anfW or nifW probes coding for the smaller subunit (= nitroge nase reductase) o f the Fe-nitr...
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تاریخ انتشار 2001