Archives of Microbiology

, Volume 167, Issue 4, pp 189–195

The [NiFe] hydrogenases of Methanococcus voltae: genes, enzymes and regulation

  • Oliver Sorgenfrei
  • Steffen Müller
  • Matthias Pfeiffer
  • Izabela Sniezko
  • A. Klein
Mini-review

DOI: 10.1007/s002030050434

Cite this article as:
Sorgenfrei, O., Müller, S., Pfeiffer, M. et al. Arch Microbiol (1997) 167: 189. doi:10.1007/s002030050434

Abstract

Methanococcus voltae carries genetic information for four [NiFe] hydrogenases. Two of the hydrogenases are predicted to contain selenocysteine on the basis of in-frame TGA codons, while the genes encoding the two other enzymes contain cysteine codons at homologous positions. Their predicted subunit compositions and their electron acceptor specificities are similar to those of the respective selenium-containing enzymes. The selenium-containing hydrogenases have been purified and characterized. Only one of them reduces the deazaflavin F420. The activity of the F420-nonreducing enzyme is exceptionally high. The selenium atom has been shown by EPR spectroscopy to be a ligand to the Ni atom in the primary reaction centers in both enzymes. The spectroscopic analyses also yielded a description of the electronic configuration around the NiFe center at different oxidation states and in the presence of the competitive inhibitor, CO. The genes encoding the selenium-free hydrogenases are expressed only in the absence of selenium. They are linked by an intergenic region in which regulatory cis elements were defined by employing reporter gene constructs and site-directed mutagenesis.

Key words [NiFe] HydrogenasesMethanococcusvoltaeArchaeaSelenocysteineSelenium-dependentgene regulationOperatorSilencerEPR

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Oliver Sorgenfrei
    • 1
  • Steffen Müller
    • 1
  • Matthias Pfeiffer
    • 1
  • Izabela Sniezko
    • 1
  • A. Klein
    • 1
  1. 1.Molekulargenetik, Fachberich Biologie, Philipps-Universität, D-35032 Marburg, Germany Tel. +49-6421-283014; Fax +49-6421-286812 e-mail: klein@molgen.biologie.uni-marburg.deGermany