Glucosylated Nucleotide Sequences from T-even Bacteriophage Deoxyribonucleic Acids.

1. The frequencies of various pyrimidine nucleotide sequences in phage-T2VG111 DNA and phage-T6 DNA have been measured. The hydroxymethylcytosine nucleotides that bear glucosyl groups in phage-T2VG111 DNA and gentiobiosyl groups in phage-T6 DNA are not randomly distributed. 2. Sequences in which two or three hydroxymethylcytosine nucleotides are terminated at both ends by purine nucleotides bear only one sugar substituent and this is attached to the first hydroxymethylcytosine when the sequences are written in the conventional notation; i.e. with the 5'-phosphate before and the 3'-phosphate after each nucleoside residue. This resembles the distribution of glucosyl residues previously found in the corresponding sequences from phage-T2 DNA. Sequences in which one hydroxymethylcytosine nucleotide is attached through the 3'-position to a purine nucleotide are more fully glucosylated in phage-T2VG111 DNA and phage-T6 DNA than in the DNA of phage T2. 3. Pyrimidine sequences from the DNA of phage T6(S) have been found to contain glucosyl but not gentiobiosyl residues. The relative amounts of the sequences isolated indicate that the distribution of the glucosyl residues in this DNA resembles that of the gentiobiosyl groups in phage-T6 DNA. 4. It is suggested that the distributions of glycosyl substituents in these T-even-phage deoxyribonucleic acids reflect the specificity requirements of the alpha-glucosyltransferases induced by the different phages. The results obtained with the DNA of phage T6(S) suggest that this phage induces the usual phage-T6 alpha-glucosyltransferase but not the phage-T6 beta-glucosyltransferase.