Selenite Assimilation into Formate Dehydrogenase H Depends on Thioredoxin Reductase in Escherichia coli

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Author(s)

    • MIHARA Hisaaki
    • Laboratory of Molecular Microbial Science, Institute for Chemical Research, Kyoto University
    • KUROKAWA Suguru
    • Laboratory of Molecular Microbial Science, Institute for Chemical Research, Kyoto University
    • NAKANO Ryuhei
    • Department of Biofunctional Chemistry, Graduate School of Natural Science and Technology, Okayama University
    • INAGAKI Kenji
    • Department of Biofunctional Chemistry, Graduate School of Natural Science and Technology, Okayama University

Abstract

<p>Escherichia coli growing under anaerobic conditions produce H-2 and CO2 by the enzymatic cleavage of formate that is produced from pyruvate at the end of glycolysis. Selenium is an integral part of formate dehydrogenase H (FDHH), which catalyses the first step in the formate hydrogen lyase (FHL) system. The genes of FHL system are transcribed only under anaerobic conditions, in the presence of a sigma(54)-dependent transcriptional activator Fh1A that binds formate as an effector molecule. Although the formate addition to the nutrient media has been an established procedure for inducing high FDHH activity, we have identified a low-salt nutrient medium containing <0.1% NaCl enabled constitutive, high expression of FDHH even without formate and D-glucose added to the medium. The novel conditions allowed us to study the effects of disrupting genes like trxB (thioredoxin reductase) or gor (glutathione reductase) on the production of FDHH activity and also reductive assimilation of selenite (SeO32-) into the selenoprotein. Despite the widely accepted hypothesis that selenite is reduced by glutathione reductase-dependent system, it was demonstrated that trxB gene was essential for FDHH production and for labelling the FDHH polypeptide with Se-75-selenite. Our present study reports for the first time the physiological involvement of thioredoxin reductase in the reductive assimilation of selenite in E. coli.</p>

Journal

  • The journal of biochemistry

    The journal of biochemistry 143(4), 467-473, 2008-04-01

    Japanese Biochemical Society

References:  38

Cited by:  3

Codes

  • NII Article ID (NAID)
    10024909223
  • NII NACSIS-CAT ID (NCID)
    AA00694073
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    0021924X
  • NDL Article ID
    026556865
  • NDL Call No.
    Z53-B472
  • Data Source
    CJP  CJPref  NDL  IR 
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