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