Streptomyces lividans 66 contains a gene for phage resistance which is similar to the phage lambda ea59 endonuclease gene.

The DNA of wild-type Streptomyces lividans 66 is degraded during electrophoresis in buffers containing traces of ferrous iron. S. lividans ZX1, a mutant selected for resistance to DNA degradation, simultaneously became sensitive to phi HAU3, a wide-host-range temperate bacteriophage. A DNA fragment conferring phi HAU3 resistance was cloned; it contains a phage resistance gene whose deduced amino acid sequence is similar to the phage lambda Ea59 endonuclease. The S. lividans phi HAU3 resistance does not seem to be a classical restriction-modification system, because no host-modified phages able to propagate on the wild-type strain could be isolated. The cloned fragment did not make the host DNA prone to degradation during electrophoresis, indicating that the two phenotypes are controlled by different genes which were deleted together from the chromosome of ZX1.