title: [FeFe]-hydrogenase maturation: HydG-catalyzed synthesis of carbon monoxide.
abstract: Biosynthesis of the unusual organometallic H-cluster at the active site of the [FeFe]-hydrogenase requires three accessory proteins, two of which are radical AdoMet enzymes (HydE, HydG) and one of which is a GTPase (HydF). We demonstrate here that HydG catalyzes the synthesis of CO using tyrosine as a substrate. CO production was detected by using deoxyhemoglobin as a reporter and monitoring the appearance of the characteristic visible spectroscopic features of carboxyhemoglobin. Assays utilizing (13)C-tyrosine were analyzed by FTIR to confirm the production of HbCO and to demonstrate that the CO product was synthesized from tyrosine. CO ligation is a common feature at the active sites of the [FeFe], [NiFe], and [Fe]-only hydrogenases; however, this is the first report of the enzymatic synthesis of CO in hydrogenase maturation.
authors.affiliation: Department of Chemistry & Biochemistry and Astrobiology Biogeocatalysis Research Center, Montana State University, Bozeman, Montana 59717, USA.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Shepard
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Duffus
authors.forename: Simon J
authors.initials: SJ
authors.lastname: George
authors.forename: Shawn E
authors.initials: SE
authors.lastname: McGlynn
authors.forename: Martin R
authors.initials: MR
authors.lastname: Challand
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Swanson
authors.forename: Peter L
authors.initials: PL
authors.lastname: Roach
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Cramer
authors.forename: John W
authors.initials: JW
authors.lastname: Peters
authors.forename: Joan B
authors.initials: JB
authors.lastname: Broderick
mesh_terms: D002248:Carbon Monoxide / Q000378:metabolism*; D002384:Catalysis; D003013:Clostridium; D029968:Escherichia coli Proteins; D006864:Hydrogenase / Q000378:metabolism*; D012436:S-Adenosylmethionine; D015534:Trans-Activators; D014443:Tyrosine / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D015534:Trans-Activators; C423908:zraR protein, E coli; D014443:Tyrosine; D012436:S-Adenosylmethionine; D002248:Carbon Monoxide; D006864:Hydrogenase