Identification of a eukaryotic‐like protein kinase gene in Archaebacteria

Primary sequence patterns based on known conserved sites in eukaryotic protein kinases were used to search for eukaryotic‐like protein kinase sequences in a six‐frame translation of the bacterial subsection of GenBank. This search identified a previously unrecognized eukaryotic‐like protein kinase gene in three related methanogenic archaebacteria, Methanococcus vannielii, M. voltae, and M. thermolithotrophicus. The proposed coding sequences are located in orthologous open reading frames (ORFs): ORF547, ORF294, and ORF114, respectively. The C‐terminus of the ORFs contains 9 of the 11 subdomains characteristically conserved within the eukaryotic protein kinase catalytic domain. The N‐terminus of the ORFs is similar to a putative glycoprotease in Pasteurella haemolytica and its homologue in Escherichia coli, the orfX gene. This is the first report of a eukaryotic‐like protein kinase sequence observed in Archaebacteria.