title: Phylogeny of Methanopyrus kandleri based on methyl coenzyme M reductase operons.
abstract: 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.
authors.affiliation: Department of Microbiology, Ohio State University, Columbus 43210, USA.
authors.forename: J
authors.initials: J
authors.lastname: Nölling
authors.forename: A
authors.initials: A
authors.lastname: Elfner
authors.forename: J R
authors.initials: JR
authors.lastname: Palmer
authors.forename: V J
authors.initials: VJ
authors.lastname: Steigerwald
authors.forename: T D
authors.initials: TD
authors.lastname: Pihl
authors.forename: J A
authors.initials: JA
authors.lastname: Lake
authors.forename: J N
authors.initials: JN
authors.lastname: Reeve
mesh_terms: D019605:Euryarchaeota / Q000145:classification* / Q000201:enzymology / Q000235:genetics; D009876:Operon; D010088:Oxidoreductases / Q000235:genetics*; D010802:Phylogeny
chemical_list: D010088:Oxidoreductases; C021572:methyl coenzyme M reductase