Organization of the RA3 conjugative transfer module. A. Transcriptional organization of the RA3 conjugative transfer module with orfs labeled according to the predicted function in the conjugation process: light grey arrows indicate homologs of Mpf system, dark grey arrows indicate proteins presumably involved in DNA replication and transfer (Dtr), and the black one marks a homolog of coupling protein VirD4. B. DNA sequence of mobCp/oriT/parS region between 9400 and 9869 nt of RA3 coordinates [GenBank: DQ401103]. Thin arrows correspond to primers used in the construction of deletion derivatives by PCR. Putative promoter motifs are boxed, and putative regulatory sequences are indicated by arrows. The inverted repeat IR-SnaBI is a part of the centromere-like sequence as the binding site for partitioning protein KorB (OB) . Highly conserved nick site is circled and the ribosome binding site and initiation codon for MobC are in bold. The oligonucleotides tested as oriT s (61 nt and 45 nt) are shown.