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Mechanism of proton transfer in [FeFe]-hydrogenase from Clostridium pasteurianum.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2011 Nov 04; Vol. 286 (44), pp. 38341-38347. Date of Electronic Publication: 2011 Sep 07. - Publication Year :
- 2011
-
Abstract
- [FeFe]-Hydrogenases are complex metalloproteins that catalyze the reversible reduction of protons to molecular hydrogen utilizing a unique diiron subcluster bridged to a [4Fe4S] subcluster. Extensive studies have concentrated on the nature and catalytic activity of the active site, yet relatively little information is available concerning the mechanism of proton transport that is required for this activity. Previously, structural characterization of [FeFe]-hydrogenase from Clostridium pasteurianum indicated a potential proton transport pathway involving four residues (Cys-299, Glu-279, Ser-319, and Glu-282) that connect the active site to the enzyme surface. Here, we demonstrate that substitution of any of these residues resulted in a drastic reduction in hydrogenase activity relative to the native enzyme, supporting the importance of these residues in catalysis. Inhibition studies of native and amino acid-substituted enzymes revealed that Zn(2+) specifically blocked proton transfer by binding to Glu-282, confirming the role of this residue in the identified pathway. In addition, all four of these residues are strictly conserved, suggesting that they may form a proton transport pathway that is common to all [FeFe]-hydrogenases.
- Subjects :
- Amino Acid Sequence
Biological Transport
Catalysis
Glutamic Acid chemistry
Iron-Sulfur Proteins chemistry
Kinetics
Molecular Conformation
Molecular Sequence Data
Mutagenesis, Site-Directed
Protons
Sequence Homology, Amino Acid
Zinc chemistry
Clostridium enzymology
Hydrogenase chemistry
Iron chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 1083-351X
- Volume :
- 286
- Issue :
- 44
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 21900241
- Full Text :
- https://doi.org/10.1074/jbc.M111.254664