title: How nitrogenase shakes--initial information about P-cluster and FeMo-cofactor normal modes from nuclear resonance vibrational spectroscopy (NRVS).
abstract: Nitrogenase catalyzes a reaction critical for life, the reduction of N(2) to 2NH(3), yet we still know relatively little about its catalytic mechanism. We have used the synchrotron technique of (57)Fe nuclear resonance vibrational spectroscopy (NRVS) to study the dynamics of the Fe-S clusters in this enzyme. The catalytic site FeMo-cofactor exhibits a strong signal near 190 cm(-)(1), where conventional Fe-S clusters have weak NRVS. This intensity is ascribed to cluster breathing modes whose frequency is raised by an interstitial atom. A variety of Fe-S stretching modes are also observed between 250 and 400 cm(-)(1). This work is the first spectroscopic information about the vibrational modes of the intact nitrogenase FeMo-cofactor and P-cluster.
authors.affiliation: Department of Applied Science, University of California, Davis, California 95616, USA.
authors.forename: Yuming
authors.initials: Y
authors.lastname: Xiao
authors.forename: Karl
authors.initials: K
authors.lastname: Fisher
authors.forename: Matt C
authors.initials: MC
authors.lastname: Smith
authors.forename: William E
authors.initials: WE
authors.lastname: Newton
authors.forename: David A
authors.initials: DA
authors.lastname: Case
authors.forename: Simon J
authors.initials: SJ
authors.lastname: George
authors.forename: Hongxin
authors.initials: H
authors.lastname: Wang
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Sturhahn
authors.forename: Ercan E
authors.initials: EE
authors.lastname: Alp
authors.forename: Jiyong
authors.initials: J
authors.lastname: Zhao
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Yoda
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Cramer
mesh_terms: D000465:Algorithms; D000641:Ammonia / Q000737:chemistry; D002384:Catalysis; D058085:Iron Compounds / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008958:Models, Molecular; D008983:Molybdoferredoxin / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D009591:Nitrogenase / Q000737:chemistry*; D013457:Sulfur Compounds / Q000737:chemistry; D013816:Thermodynamics; D014732:Vibration
chemical_list: D058085:Iron Compounds; D008983:Molybdoferredoxin; D013457:Sulfur Compounds; D000641:Ammonia; D009591:Nitrogenase; D009584:Nitrogen