Characterization of pPvu1, the autonomous plasmid from Proteus vulgaris that carries the genes of the PvuII restriction-modification system.

Plasmid pPvu1 from Proteus vulgaris carries the genes of the PvuII restriction-modification system [Blumenthal et al., J. Bacteriol. 164 (1985) 501-509]. This report focuses on physical and functional features of the 4.84-kb plasmid, which shows a composite genetic architecture. Plasmid pPvu1 has a replication origin and an incompatibility locus that each function in Escherichia coli, and an apparent cer recombination site. The replication origin includes a possible RNA I gene, and the incompatibility locus closely resembles a rom gene. These loci show substantial sequence similarity to corresponding loci from the E. coli plasmids P15A, ColEI and pSC101, and closely flank the PvuII genes. The close association between a recombinational locus and the PvuII genes has implications for their mobility.