4c3o
Structure and function of an oxygen tolerant NiFe hydrogenase from SalmonellaStructure and function of an oxygen tolerant NiFe hydrogenase from Salmonella
Structural highlights
FunctionPublication Abstract from PubMedSalmonella enterica is an opportunistic pathogen that produces a [NiFe]-hydrogenase under aerobic conditions. Here, genetic engineering approaches were used to facilitate isolation of this enzyme, termed Hyd-5. The crystal structure was determined to a resolution of 3.2 A and the hydrogenase was observed to comprise associated large and small subunits. The structure indicated that residue H229 from the large subunit was close to the proximal [4Fe-3S] cluster in the small subunit. In addition, H229 was observed to lie close to a buried glutamic acid (E73), which is conserved in oxygen-tolerant hydrogenases. Residues H229 and E73 of the Hyd-5 large subunit were found to be important in both hydrogen oxidation activity and the oxygen tolerance mechanism. Substitution of H229 or E73 with alanine led to a loss in the ability of Hyd-5 to oxidise hydrogen in air. Furthermore, the H229A variant was found to have lost the overpotential requirement for activity that is always observed with oxygen-tolerant [NiFe]-hydrogenases. It is possible that H229 has a role in stabilising the super-oxidised form of the proximal cluster in the presence of oxygen, and it is proposed that E73 could play a supporting role in fine-tuning the chemistry of H229 to enable this function. How the structure of the large subunit controls function in an oxygen-tolerant [NiFe]-hydrogenase.,Bowman L, Flanagan L, Fyfe PK, Parkin A, Hunter WN, Sargent F Biochem J. 2014 Jan 16. PMID:24428762[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
|
| ||||||||||||||||||