Cleavage of Nonglucosylated Bacteriophage T4 deoxyribonucleic acid by Restriction Endonuclease Eco RI.

DNAs lacking the glucosyl modification (Glc-) and additionally lacking the 6-methylaminopurine (N6-methyladenine) modification (Glc-, MeAde-) were prepared from appropriate T4 mutants. These DNAs were cleaved by the purified restriction endonuclease Eco TI from Escherichia coli. Normally modified DNA (Glc+, MeAde+) was not attached. The Eco RII and the hemophilus enzymes Hin dII and Hin dIII do not attack Glc-, MeAde- T DNA, possibly due to the presence of 6-hydroxymethylcytosine. Eco RI produces approximately 40 specific fragments from Glc- DNA ranging in molecular weights from 0.3 to 10.5 X 10-6.