[FeFe]-hydrogenase maturation: HydG-catalyzed synthesis of carbon monoxide

Shepard, Eric M., Duffus, Benjamin R., George, Simon J., McGlynn, Shawn E., Challand, Martin R., Swanson, Kevin D., Roach, Peter L., Cramer, Stephen P., Peters, John W. and Broderick, Joan B. (2010) [FeFe]-hydrogenase maturation: HydG-catalyzed synthesis of carbon monoxide. Journal of the American Chemical Society, 132 (27), 9247-9249. (doi:10.1021/ja1012273). (PMID:20565074)

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 13C-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.

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Contributors

Author: Peter L. Roach

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