N2 Fixation by Streptomyces thermoautotrophicus Involves a Molybdenum-Dinitrogenase and a Manganese-Superoxide Oxidoreductase That Couple N2Reduction to the Oxidation of Superoxide Produced from O2by a Molybdenum-CO Dehydrogenase
Year: 1997
Type: article
Abstract: N2 fixation by Streptomyces thermoautotrophicus follows the equation N2 + 4-12MgATP + 8H+ + 8e- --> 2NH3 + H2 + 4-12MgADP + 4-12Pi and exhibits features which are not obvious in the diazotrophic bacteria studied so far. The reaction is coupled to the oxidation of carbon monoxide (CO) by a molybdenum-containing CO dehydrogenase that transfers the electrons derived from CO oxidation to O2, thereby producing superoxide anion radicals (O-2). A manganese-containing superoxide oxidoreductase reoxidizes the O-2 anions to O2 and transfers the electrons to a MoFeS-dinitrogenase for the reduction of N2 to ammonium. Among the most striking properties of the S. thermoautotrophicus nitrogenase system are the dependence on O2 and O-2, the complete insensitivity of all components involved toward O2 and H2O2, the inability to reduce ethine or ethene, and a low MgATP requirement. In addition, the subunit structure of the S. thermoautotrophicus nitrogenase components and the polypeptides involved seem to be dissimilar from the known nitrogenases.
Source: Journal of Biological Chemistry
Authors: Markus Ribbe, Dilip Gadkari, Ortwin Meyer
Institution: University of Bayreuth
Language: English
Subfield: Biochemistry
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
OpenAlex ID: W2135938280