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Descripción
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| Some rhizobia induce a hydrogen-uptake system with a [NiFe] hydrogenase that catalyses the oxidation of H2 evolved during the N2 fixation process. In R. leguminosarum bv viciae the genetic determinants for hydrogenase biosynthesis include 18 genes (hupSLCDE FGHIJKhypABF CDEX) clustered in the symbiotic plasmid (Ruiz-Argu?eso et al ., 2001). Whereas HypC is present in all NiFe hydrogenases, HupF and HupK are only present in those systems in which hydrogenase is synthesized in the presence of O2. HupF is a chaperone that contributes to stabilize HupL during hydrogenase biosynthesis (Albareda et al ., 2012) and HupK is a scaffolding protein for the transfer of precursor cofactor to HupL (Imperial et al ., 1993; Ludwig et al ., 2009). Co-purification experiments have demonstrated a direct HypC-HupK interaction, and also a HupK-dependent complex involving HypC and HupL. Hydrogenase activity of microaerobic (1% O2) cultures of mutant strains harboring ?hypC). In contrast, under symbiotic conditions, the alteration of L33 had no significant effect on hydrogenase maturation indicating that this residue might be necessary for the adaptation of hydrogenase biosynthesis to the presence of O2. HupK variants affected in residues participating in the precursor cofactor binding site (C57, C357 and F360) showed hydrogenase-deficient phenotype under microaerobic conditions. In contrast, bacteroids induced by the same mutants showed hydrogenase levels similar to those in the wild-type strain. These results indicate that bacteroids might use a HupK-independent pathway similar to that described in E . coli for cofactor transfer during hydrogenase biosynthesis. | |
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Internacional
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Si |
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Nombre congreso
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10th International Hydrogenase Conference |
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Tipo de participación
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960 |
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Lugar del congreso
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Szeged, Hungría |
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Revisores
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Si |
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ISBN o ISSN
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0000-0000 |
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DOI
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Fecha inicio congreso
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08/07/2013 |
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Fecha fin congreso
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12/07/2013 |
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Desde la página
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46 |
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Hasta la página
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46 |
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Título de las actas
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Book of Abstracts |