title: Rhizobium leguminosarum bv. viciae hypA gene is specifically expressed in pea (Pisum sativum) bacteroids and required for hydrogenase activity and processing.
abstract: Rhizobium leguminosarum bv. viciae strain UPM791 induces in symbiosis with peas the synthesis of a nickel-containing hydrogenase which recycles the hydrogen evolved by nitrogenase. The genes required for synthesis of this hydrogenase, hupSLCDEFGHIJKhypABFCDEX, are clustered in the symbiotic plasmid. Analysis of a hypA-deficient mutant showed that HypA is essential for symbiotic hydrogenase activity and required for correct processing of the hydrogenase large subunit. Unlike other microoxically induced hyp genes, the hypA gene was only expressed in pea bacteroids from its own promoter. The hypA mRNA 5' end was mapped 109 bp upstream of the translational start codon. This distinct pattern of expression suggests a different role for HypA and the remaining Hyp proteins in hydrogenase synthesis.
authors.affiliation: Departamento de Biotecnología, Escuela Técnica Superior de Ingenieros Agrónomos, Universidad Politécnica de Madrid, Spain.
authors.forename: Y
authors.initials: Y
authors.lastname: Hernando
authors.forename: J
authors.initials: J
authors.lastname: Palacios
authors.forename: J
authors.initials: J
authors.lastname: Imperial
authors.forename: T
authors.initials: T
authors.lastname: Ruiz-Argüeso
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D001439:Bacteroides / Q000235:genetics*; D001483:Base Sequence; D005798:Genes, Bacterial; D006864:Hydrogenase / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D018532:Pisum sativum / Q000382:microbiology*; D011401:Promoter Regions, Genetic / Q000235:genetics; D016961:Rhizobium leguminosarum / Q000201:enzymology / Q000235:genetics*; D016415:Sequence Alignment; D013559:Symbiosis / Q000235:genetics / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D006864:Hydrogenase