Hydrogenases structure

Frenking G, Cremer D (1990) The Chemistry of the Nobles Gas Elements Helium, Neon, and Argon - Experimental Facts and Theoretical Predictions. 73 17-96 Frey M (1998) Nickel-Iron Hydrogenases Structural and Functional Properties. 90 97-126 Fricke B (1975) Superheavy Elements. 21 89-144... 

Two [Fe] hydrogenase structures have so far been determined from C. pasteurianum (Cp) (Peters et al. 1998) and D. desulfuricans (Dd) (Nicolet et al. 1999). They have in common a large domain, which contains the catalytic site and three [4Fe-4S] iron sulfur clusters. The catalytic site and the closest (proximal) cluster are deeply buried inside the protein between two domains (or lobes), with access to a third, ferredoxin-like, domain that contains the two remaining (medial and distal) clusters. By contrast with [NiFe] hydrogenases the proximal [4Fe-4S] cluster is directly bridged to the bin-uclear active site by a cysteic thiolate (Fig. 6.12). 

Minimal hydrogenase The part of a hydrogenase structure that is found in all hydrogenases of a particular type, and which is therefore proposed to be the essential part for its function. For example in the NiFe hydrogenases, this comprises the NiFe catalytic centre in the large subunit, and the proximal [4Fe-4S] cluster in the small subunit. 

Brito, B., Palacios, J. -M., Hidalgo, E., Imperial, J. and Ruiz-Argueso, T. (1994) Nickel availability to Pea [Pisum sativum) plants limits hydrogenase activity of Rhizobium legumi-nosarum viciae bacteroids, by affecting the processing of the hydrogenase structural subunits. J. Bacterial., 176, 5297-303. 

Fu, C. and Maier, R. J. (1993) A genetic region downstream of the hydrogenase structural genes of Bradyrhizobium japonicum that is required for hydrogenase processing. J. 

Frey M. 1998. Nickel-iron hydrogenases structural and functional properties. Struct Bonding 90 98-126. 

Nicolet Y, Cavazza C, Fontecilla-Camps JC (2002) Fe-only hydrogenases structure, function and evolution. J. Inorg. Biochem. 91 1-8... 

These features demonstrate how important it is to study and understand hydrogenase structure and function when designing biomimetic (or bioinspired) systems for efficient hydrogen generation or utilization. This section will give insight into this class of enzymes. 

Ogata H, Lubitz W, Higuchi Y. [NiFe] Hydrogenases structural and spectroscopic studies of the reaction mechanism. Dalton Trans. 2009 (27) 7577-87. 

Cao ZX, Hall MB. Modeling the active sites in metalloenzymes. 3. Density functional calculations on models for [Fe]-hydrogenase structures and vibrational frequencies of the observed redox forms and the reaction mechanism at the diiron active center. J Am Chem Soc. 2001 123(16) 3734-42. 

A second [FeNi]-hydrogenase structure, from Desulfovibrio vulgaris (Miyazaki F), revealed a similar active site cluster (PDB lh2a) [61]. Like the structure of the D. gigas enzyme, the active site cluster consists of a nickel ion coordinated by four cysteine residues, two of which form a bridge to the iron ion. The iron ion has three nonprotein ligands that are proposed to be the diatomics S=0, CO and CN mole-... 

Figure 9 Construction of plasmid pKE4-9SH. The promoter region and the clostridial hydrogenase structure gene were amplified by PCR. Both fragments were ligated at their BamHI restriction sites and cloned into the shuttle vector pKE4.

Cauvin, B., Colbeau, A. and Vignais, P.M. (1991). The hydrogenase structural operon in Rhodobacter capsulatus contains a third gene, hupM, necessary for the formation hydrogenase. Mol. Microbiol. 5, 2519-2527. 

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