Deoxyribonucleic acid methylation in mycobacteria

Abstract

Deoxyribonucleic acid modification in 6 strains of mycobacteria was investigated. The presence of 5-methylcytosine in the virulent strain Mycobacterium tuberculosis H(37)R(v) and its absence in the avirulent strain M. tuberculosis H(37)R(a) and other saprophytic, fast-growing mycobacteria appear to be the salient features. However, deoxyribonucleic acid from M. smegmatis SN2 lysogenized with the temperate phage I3 showed the presence of 5-methylcytosine. All of the strains had N6-methyladenine.