Structure of the DNA of five bacteriophages infecting Micromonospora.

The physical maps of the DNA of five bacteriophages (Mm1, OM2, OM3, Mm4 and Mm5) which infect Micromonospora are presented. The restriction analyses showed that all of them had linear, double-stranded DNA, but only four (Mm1, OM2, Mm4 and Mm5) presented cohesive ends. The phages showed no relationship in terms of their restriction maps or of DNA-DNA hybridization, with the exception of Mm4 and Mm5, which resulted to be very similar. Phage Mm5 presented a high level of resistance to chelating agents, although deletion mutants, all of them showing a single detection of 1.4 kb, were obtained by using extremely selective conditions.