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A region of the IncHI2 plasmid R478, encoding the phenotypes of tellurite resistance (Te-r), phage inhibition (Phi), and colicin resistance (PacB), was cloned and sequenced. Analysis indicated seven open reading frames (ORFs), whose genes were designated terZ, -A, -B, -C, -D, -E, and -F. Five of these predicted ORFs (A to E) had extensive amino acid homology with the previously reported ORFs of the IncHI2 Te-r operon from plasmid pMER610. There were domains of highly conserved amino acid residues within the group TerA, -D, -E, and -F and within TerD, -E, and -Z, but no consensus could be found among all five putative polypeptides. There mere also regions of good identity and similarity between individual pairs of ORFs which was not reflected in the multiple alignments. The three phenotypes were expressed in Escherichia coli DH5 alpha by an 8.4-kb EcoRI insert subcloned from a cosmid of R478. The latter insert was clonable only as a double insertion with a 4.5-kb fragment, and forced...
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