A study of the nucleic acid of bacteriophage T7

A T7 bacteriophage preparation has been obtained with a P per infective particle of 8.2 × 10^(−18) g. Only 71% of the P of the preparation is present as DNA. No RNA is present. DNA was prepared from T7 in 70% yield by denaturation of the virus with urea plus dodecyl sulfate, followed by deproteinization by chloroform. The molar proportions of bases in the DNA are: deoxyadenylic acid, 1.04; thymidylic acid, 1.04; deoxycytidylic acid, 0.96; deoxyguanylic acid, 0.96. During complete digestion of the T7 DNA with pancreatic deoxyribonuclease, 19.4% of the phosphate diester bonds were split. After fractionation of the digest by ion-exchange chromatography, 5.9% of the P of the digest was recovered as dinucleotides. These were fractionated and their relative proportions determined. Four of the dinucleotide fractions were analyzed for their isomeric position