Characterisation of mycobacteriophage ATCC 11759. Unusual physiocochemical properties of its DNA.

Growth conditions and a purification procedure for mycobacteriophage ATCC 11759, a lytic phage for Mycobacterium smegmatis, are described. The phage is a large DNA phage with a very long tail (240 nm). A study of its DNA revealed three interesting features. 1. After denaturation the DNA molecule yields two strands of different buoyant densities. 2. The native DNA has unusual physical properties: its buoyant density in CsC1 is very low (1.654 g/cm3), its sedimentation rate is lower than expected for the molecular weight, its thermal stability at low ionic strength is high. 3. The DNA (in its native form or after reannealing) is resistant to various restriction endonucleases.