title: Biosynthesis of Salmonella enterica [NiFe]-hydrogenase-5: probing the roles of system-specific accessory proteins.
abstract: A subset of bacterial [NiFe]-hydrogenases have been shown to be capable of activating dihydrogen-catalysis under aerobic conditions; however, it remains relatively unclear how the assembly and activation of these enzymes is carried out in the presence of air. Acquiring this knowledge is important if a generic method for achieving production of O2-resistant [NiFe]-hydrogenases within heterologous hosts is to be developed. Salmonella enterica serovar Typhimurium synthesizes the [NiFe]-hydrogenase-5 (Hyd-5) enzyme under aerobic conditions. As well as structural genes, the Hyd-5 operon also contains several accessory genes that are predicted to be involved in different stages of biosynthesis of the enzyme. In this work, deletions in the hydF, hydG, and hydH genes have been constructed. The hydF gene encodes a protein related to Ralstonia eutropha HoxO, which is known to interact with the small subunit of a [NiFe]-hydrogenase. HydG is predicted to be a fusion of the R. eutropha HoxQ and HoxR proteins, both of which have been implicated in the biosynthesis of an O2-tolerant hydrogenase, and HydH is a homologue of R. eutropha HoxV, which is a scaffold for [NiFe] cofactor assembly. It is shown here that HydG and HydH play essential roles in Hyd-5 biosynthesis. Hyd-5 can be isolated and characterized from a ΔhydF strain, indicating that HydF may not play the same vital role as the orthologous HoxO. This study, therefore, emphasises differences that can be observed when comparing the function of hydrogenase maturases in different biological systems.
authors: Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, UK.
authors: Lisa
authors: L
authors: Bowman
authors: Department of Chemistry, University of York, Heslington, York, YO10 5DD, England, UK.
authors: Jonathan
authors: J
authors: Balbach
authors: Department of Chemistry, University of York, Heslington, York, YO10 5DD, England, UK.
authors: Julia
authors: J
authors: Walton
authors: Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, UK.
authors: Frank
authors: F
authors: Sargent
authors: Department of Chemistry, University of York, Heslington, York, YO10 5DD, England, UK. alison.parkin@york.ac.uk.
authors: Alison
authors: A
authors: Parkin
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D001426:Bacterial Proteins / Q000378:metabolism; D006864:Hydrogenase / Q000096:biosynthesis* / Q000378:metabolism; D010084:Oxidation-Reduction; D019779:Salmonella enterica / Q000201:enzymology* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C043296:nickel-iron hydrogenase; D006864:Hydrogenase
keywords: Biosynthesis; Electrochemistry; Hydrogenase; Iron–sulfur cluster; Metallocenter assembly