Phylogeny of Methanopyrus kandleri based on methyl coenzyme M reductase operons

Int J Syst Bacteriol. 1996 Oct;46(4):1170-3. doi: 10.1099/00207713-46-4-1170.


The mcrBDCGA operon that encodes methyl coenzyme M reductase (MR) in the hyperthermophile Methanopyrus kandleri was cloned and sequenced. The results of a phylogenetic analysis of the nine MR sequences now available support the position that M. kandleri is a separate methanogen lineage. As in other methanogens, the M. kandleri mcr operon is located immediately upstream of the mtrE gene, the promoter-proximal gene in an operon that encodes the N5-methyltetrahydromethanopterin:coenzyme M methyltransferase that catalyzes the step preceding the MR-catalyzed reaction in methanogenesis. In contrast to other methanogens and hyperthermophilic members of the Archaea, CG dinucleotides and CG-containing codons occur frequently in M. kandleri DNA. The MR subunit-encoding genes are preceded by sequences consistent with ribosome binding sites, indicating that mRNA-rRNA base pairing can still direct translation initiation in cells growing at temperatures above 100 degrees C.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Euryarchaeota / classification*
  • Euryarchaeota / enzymology
  • Euryarchaeota / genetics
  • Operon*
  • Oxidoreductases / genetics*
  • Phylogeny


  • Oxidoreductases
  • methyl coenzyme M reductase