Nitrogenase reactivity with P-cluster variants.
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.
Hu
Yilin
Y
Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA.
Corbett
Mary C
MC
Fay
Aaron W
AW
Webber
Jerome A
JA
Hedman
Britt
B
Hodgson
Keith O
KO
Ribbe
Markus W
MW
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
D008667:Metalloproteins; D008983:Molybdoferredoxin; D009591:Nitrogenase