The sequences of the traJ gene and the 5' end of the traY gene of the resistance plasmid R1

The traJ gene and the 5' end of the neighbouring traY gene of the resistance plasmid R1 were sequenced. Both structural genes show relatively little homology with the corresponding sequences of the related F plasmid. At the amino acid level sufficient homology is detected to allow an assignment of the two genes in R1. In traJ two methionine codons have to be regarded as potential chain initiation signals. Because of the analogy with the F plasmid sequence the second ATG is believed to be the main translational start site. The traJ gene codes for 228 amino acids. The 5' untranslated region of the traJ gene of R1 is highly homologous to the corresponding sequence in F indicating that it fulfills an important role in regulation. The transcription of the traY-Z operon starts in the structural gene of traJ. The amino terminal part of the TraY protein shows only limited homology with the F factor counterpart. However, the few conserved amino acids are a strong indication that our sequence contains the traY gene of R1.