Observatorio de I+D+i UPM

Memorias de investigación
Communications at congresses:
Analysis of the molecular basis of nickel homeostasis in Rhizobium leguminosarum vb. Viciae.
Year:2008
Research Areas
  • Microbiology
Information
Abstract
Nickel is an essential element for different biological processes. Enzymes with nickel atom(s) in their active site participate in urea hydrolysis, oxidation of molecular hydrogen and detoxification of superoxide anion radicals. Nickel transport is a challenge for microorganisms since, although essential, high intracellular levels of this metal are toxic. For this reason, bacteria have developed high affinity nickel transporters as well as nickel-specific detoxification systems. In Rhizobium leguminosarum bv. viciae, a nickel-dependent hydrogenase is induced in pea (Pisum sativum) bacteroids. Symbiotic hydrogen uptake is limited by nickel availability to the bacteroids (Brito et al., 1994), and this nickel-dependent limitation is partly dependent on the plant host (Brito et al., 2008). Proteins involved in nickel transport for hydrogenase synthesis have not been described in R. leguminosarum. One of the putative candidates for this role is HupE, a predicted membrane protein that shows a histidine-rich domain similar to those involved in nickel transporters like HoxN from Ralstonia eutropha or NixA from Helicobacter pylori. In R. leguminosarum bv. viciae UPM791, the gene hupE is part of the hydrogenase gene cluster located in the symbiotic plasmid, whereas a second hupE-like gene, hupE2, lies in the pRLUPM791b plasmid. In addition, this bacterium contains an rcnRA system in the chromosome. In this work, we report the characterization of HupE/HupE2 as a novel class of nickel transporter involved in hydrogen oxidation. In these proteins, histidine residues essential for HupE functionality have been identified. On the other hand, analysis of expression of the rcnRA operon has revealed that these genes are overexpressed in response to high levels of nickel or cobalt in the culture medium. This mode of regulation is consistent with the purported role of these genes as part of a Ni/Co efflux system.
International
Si
Congress
8th European Nitrogen Fixation Conference
960
Place
Gante (Bélgica)
Reviewers
Si
ISBN/ISSN
CDP08UPM
Start Date
30/08/2008
End Date
03/09/2008
From page
247
To page
247
Book of abstracts of 8th European Nitrogen Fixation Conference
Participants
  • Participante: Rosa Isabel Prieto Carbajo (Universidad Politecnica de Madrid)
  • Autor: Maria Belen Brito Lopez (UPM)
  • Autor: Tomas-Andres Ruiz Argueso (UPM)
  • Autor: Juan Imperial Ródenas (UPM)
  • Participante: Ana Isabel Hidalgo
  • Autor: Ezequiel Cabrera Ordoñez (UPM)
  • Autor: Jose Manuel Palacios Alberti (UPM)
Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: Asociaciones simbióticas planta-microorganismo
  • Departamento: Biotecnología
  • Centro o Instituto I+D+i: Centro de Biotecnología y Genómica de Plantas, CBGP
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