ISOLATION AND CHARACTERIZATION OF PLASMID PSW200 FROM ERWINIA-STEWARTII

The nucleotide sequence of pSW200 of Erwinia stewartii SW2 was determi ned. This plasmid is 4367 bp long, consisting of four mobilization gen es, mobCABD, and an origin of replication homologous to those of ColE1 -type plasmids. The plasmid also contains a region of forty-one 15-bp repeats. Deleting this region does not affect the stability or the cop y number when maintained as sole plasmid in the cell. However, the pla smid is rapidly lost when a homoplasmid with the intact repeat region is introduced into the cell. The function of this region may provide p SW200 an advantage in competing with an incompatible plasmid in the ce ll. (C) 1998 Academic Press.