title: Nitrogenase reactivity with P-cluster variants.
abstract: Nitrogenase is a multicomponent metalloenzyme that catalyzes the conversion of atmospheric dinitrogen to ammonia. For decades, it has been generally believed that the [8Fe-7S] P-cluster of nitrogenase component 1 is indispensable for nitrogenase activity. In this study, we identified two catalytically active P-cluster variants by activity assays, metal analysis, and EPR spectroscopic studies. Further, we showed that both P-cluster variants resemble [4Fe-4S]-like centers based on x-ray absorption spectroscopic experiments. We believe that our findings challenge the dogma that the standard P-cluster is the only cluster species capable of supporting substrate reduction at the FeMo cofactor and provide important insights into the general mechanism of nitrogenase catalysis and assembly.
authors.affiliation: Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA.
authors.forename: Yilin
authors.initials: Y
authors.lastname: Hu
authors.forename: Mary C
authors.initials: MC
authors.lastname: Corbett
authors.forename: Aaron W
authors.initials: AW
authors.lastname: Fay
authors.forename: Jerome A
authors.initials: JA
authors.lastname: Webber
authors.forename: Britt
authors.initials: B
authors.lastname: Hedman
authors.forename: Keith O
authors.initials: KO
authors.lastname: Hodgson
authors.forename: Markus W
authors.initials: MW
authors.lastname: Ribbe
mesh_terms: D016948:Azotobacter vinelandii / Q000201:enzymology*; D002384:Catalysis; D008667:Metalloproteins / Q000737:chemistry* / Q000235:genetics; D008983:Molybdoferredoxin / Q000737:chemistry* / Q000235:genetics; D009591:Nitrogenase / Q000737:chemistry* / Q000235:genetics
chemical_list: D008667:Metalloproteins; D008983:Molybdoferredoxin; D009591:Nitrogenase