[FeFe]-hydrogenase maturation: HydG-catalyzed synthesis of carbon monoxide.
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.
Shepard
Eric M
EM
Department of Chemistry & Biochemistry and Astrobiology Biogeocatalysis Research Center, Montana State University, Bozeman, Montana 59717, USA.
Duffus
Benjamin R
BR
George
Simon J
SJ
McGlynn
Shawn E
SE
Challand
Martin R
MR
Swanson
Kevin D
KD
Roach
Peter L
PL
Cramer
Stephen P
SP
Peters
John W
JW
Broderick
Joan B
JB
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
D029968:Escherichia coli Proteins; D015534:Trans-Activators; C423908:zraR protein, E coli; D014443:Tyrosine; D012436:S-Adenosylmethionine; D002248:Carbon Monoxide; D006864:Hydrogenase