Role of the NiFe Hydrogenase Hya in Oxidative Stress Defense in Geobacter sulfurreducens

Pier-Luc Tremblay, Derek R. Lovley

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Abstract

Geobacter sulfurreducens, an Fe(III)-reducing deltaproteobacterium found in anoxic subsurface environments, contains 4 NiFe hydrogenases. Hyb, a periplasmically oriented membrane-bound NiFe hydrogenase, is essential for hydrogen-dependent growth. The functions of the three other hydrogenases are unknown. We show here that the other periplasmically oriented membrane-bound NiFe hydrogenase, Hya, is necessary for growth after exposure to oxidative stress when hydrogen or a highly limiting concentration of acetate is the electron source. The beneficial impact of Hya on growth was dependent on the presence of H-2 in the atmosphere. Moreover, the Hya-deficient strain was more sensitive to the presence of superoxide or hydrogen peroxide. Hya was also required to safeguard Hyb hydrogen oxidation activity after exposure to O-2. Overexpression studies demonstrated that Hya was more resistant to oxidative stress than Hyb. Overexpression of Hya also resulted in the creation of a recombinant strain better fitted for exposure to oxidative stress than wild-type G. sulfurreducens. These results demonstrate that one of the physiological roles of the O-2-resistant Hya is to participate in the oxidative stress defense of G. sulfurreducens.
Original languageEnglish
JournalJournal of Bacteriology
Volume194
Issue number9
Pages (from-to)2248-2253
ISSN0021-9193
DOIs
Publication statusPublished - 2012
Externally publishedYes

Keywords

  • Eubacteria Bacteria Microorganisms (Bacteria, Eubacteria, Microorganisms) - Dissimilatory Sulfate or Sulfur Reducers [06810] Geobacter sulfurreducens species
  • acetate 71-50-1
  • Hya
  • hydrogen 1333-74-0
  • hydrogen peroxide 7722-84-1
  • oxygen 7782-44-7
  • superoxide 11062-77-4
  • 10060, Biochemistry studies - General
  • 10066, Biochemistry studies - Lipids
  • 10802, Enzymes - General and comparative studies: coenzymes
  • 31000, Physiology and biochemistry of bacteria
  • Biochemistry and Molecular Biophysics
  • Enzymology

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