FIG 2 .

Characterization of phage T4 DNA modification. (A) Phage T4(glc-HMC), T4(HMC), and T4(C) DNA left untreated (−) or treated with (+) restriction enzymes AluI (top), which cleaves unmodified DNA; MspJI (middle), which cleaves HMC-containing DNA; or T4 glucosyltransferase (bottom), which increases the mobility of HMC-containing DNA by the addition of glucose groups. The arrows indicate the mobility shift due to glucose attachment. (B) Analysis of phage T4 DNA modification by single-molecule sequencing. Results are summarized for each genome by mapping IPD ratios at each base for each of the T4 strains studied. The coloration of each base is shown by the key at the bottom left. The T4 nucleotide sequence runs from top to bottom for each of the four genomes. The distance each colored point is displaced from the center indicates the IPD ratio (scale at bottom; leftward for the reverse strand, rightward for the forward strand). Examples of interpulse distances (indicative of modification) are shown to the right for a short segment of the T4 genome. Bars indicate the magnitude of the IPD ratio (upward for the forward strand and downward for the reverse strand). A 5′ GATC 3′ site of DAM methylation is highlighted in yellow. (C) Violin plot showing IPD ratios of A residues at 5′ GATC 3′ sequences.