Organization of Methanobacterium thermoautotrophicum bacteriophage psi M1 DNA

Summary M1 is a virulent bacteriophage of Methanobacterium thermoautotrophicum strain Marburg. Restriction enzyme analysis of the linear, 30.4 kb phage DNA led to a circular map of the 27.1 kb M1 genome. M1 is thus circularly permuted and exhibits terminal redundancy of approximately 3 kb. Packaging of M1 DNA from a concatemeric precursor initiates at the pac site which was identified at coordinate 4.6 kb on the circular genome map. It proceeds clockwise for at least five packaging rounds. Headful packaging was also shown for M2, a phage variant with a 0.7 kb deletion at coordinate 23.25 on the map.