Plasmid R394 is a Cointegrate

Abstract
Plasmids R394a and R394b [isolated from Escherichia coli], which cointegrate to form R394 are described. They have MW of 102 .+-. 4 and 11.0 .+-. 0.4 MDal [megadaltons], belong to the T and N incompatibility groups and confer resistance to kanamycin and ampicillin, respectively. R394a is self transmissible and mobilizes R394b, which is non-self transmissible. These findings clarify anomalies in the behavior of R394 and support suggestions based on the properties of variant phages derived from R394.