MICROBIAL GENES HOMOLOGOUS TO THE PEPTIDYL-TRANSFER-RNA HYDROLASE-ENCODING GENE OF ESCHERICHIA-COLI

We have cloned and determined the nucleotide (nt) sequences of the gen es encoding peptidyl-tRNA hydrolase (Pth) homologues of Salmonella typ hi (St) and the Lyme disease spirochaete, Borrelia burgdorferi (Bb). W e also completed the nt sequence of a pth homologous gene contained in a Chlamydia trachomatis (Ct) clone identified in the databanks. The o pen reading frames (ORFs) of the Pth homologues encode putative polype ptides of 194 (St), 188 (Bb) and 194 (Ct) amino acids exhibiting signi ficant identity with Escherichia coli (Ec) Pth. Together with the prod ucts of two previously unidentified ORFs from Bacillus subtilis and Sa ccharomyces cerevisiae, and the recently recognized Haemophilus influe nzae and Mycoplasma genitalium pth genes, these seven putative polypep tides and the Ec Pth form a group of homologous basic proteins spannin g eubacteria and eukaryota which can be defined by at least three cons erved regions. Previously known Ec pth mutations were located in highl y conserved residues.