A model for interaction of the pWTY27 RepA and the iteron. The replication origin of plasmid pWTY27 contains multiple directed and inverted repeat sequences (DRs and IRs, Figure 2a). The IR2 is a long discontinous inverted-repeat sequence and may fold back itself during initiation of replication. Since there are six unbound sites (see Figure 2a) and RepA is a large protein (522 amino acids), we suggest that five RepA molecules (indicated by filled ovals) may bind to the folding-back IR2 region leaving six unbound sites (indicated by arrowheads).
Wang et al. BMC Microbiology 2012 12:253 doi:10.1186/1471-2180-12-253