Nucleotide sequences of the R1-19 plasmid transfer genes traM, finP, traJ, and traY and the traYZ promoter

Abstract

The complete nucleotide sequences of the R1 drd-19 (R1-19) plasmid transfer genes traM, finP, traJ, and traY and the region encoding the traYZ promoter were determined. The traM protein from R1-19 was similar to the 127-amino-acid traM product from the conjugative plasmid F; only 28 residues were not identical. finP, a negative regulatory element of the traJ gene, contained a 12-base-pair inverted repeat identical to that found in the F plasmid, but differed in the 7 base pairs found between the repeats. The traJ gene and the traYZ promoter (the site of transcriptional stimulation by the traJ product) were completely different from the equivalent sequences in plasmid F. Galactokinase fusion studies of the traYZ promoter indicated that the R1-19 and F plasmids have analogous but not homologous traYZ promoter strengths and regulation. The traY protein from R1-19 was 44 residues shorter than the traY product from plasmid F, but there was some homology within the C-terminal halves of the traY gene products. The predicted translational start codon for the traY gene is GUG.