title: The Radical SAM Enzyme HydG Requires Cysteine and a Dangler Iron for Generating an Organometallic Precursor to the [FeFe]-Hydrogenase H-Cluster.
abstract: Three maturase enzymes-HydE, HydF, and HydG-synthesize and insert the organometallic component of the [FeFe]-hydrogenase active site (the H-cluster). HydG generates the first organometallic intermediates in this process, ultimately producing an [Fe(CO)2(CN)] complex. A limitation in understanding the mechanism by which this complex forms has been uncertainty regarding the precise metallocluster composition of HydG that comprises active enzyme. We herein show that the HydG auxiliary cluster must bind both l-cysteine and a dangler Fe in order to generate the [Fe(CO)2(CN)] product. These findings support a mechanistic framework in which a [(Cys)Fe(CO)2(CN)](-) species is a key intermediate in H-cluster maturation.
authors.affiliation: Department of Chemistry, University of California, Davis , Davis, California 95616, United States.
authors.forename: Daniel L M
authors.initials: DL
authors.lastname: Suess
authors.affiliation: Department of Chemistry, University of California, Davis , Davis, California 95616, United States.
authors.forename: Cindy C
authors.initials: CC
authors.lastname: Pham
authors.forename: Ingmar
authors.initials: I
authors.lastname: Bürstel
authors.forename: James R
authors.initials: JR
authors.lastname: Swartz
authors.affiliation: Department of Chemistry, University of California, Davis , Davis, California 95616, United States.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Cramer
authors.affiliation: Department of Chemistry, University of California, Davis , Davis, California 95616, United States.
authors.forename: R David
authors.initials: RD
authors.lastname: Britt
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D003545:Cysteine / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D006864:Hydrogenase / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D012436:S-Adenosylmethionine / Q000737:chemistry*; D015534:Trans-Activators / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D009942:Organometallic Compounds; D015534:Trans-Activators; D012436:S-Adenosylmethionine; D007501:Iron; C118830:iron hydrogenase; D006864:Hydrogenase; D003545:Cysteine