Nucleotide sequence analysis of DNA. XI. The 3' terminal sequences of bacteriophage lambda and phi 80 DNA

Two procedures have been developed and applied to the determination of the 3′ terminal sequences of λ DNA and φ80 DNA. In the first procedure, each 3′ terminus was specifically labeled with a single ³²P-nucleotide. Radioactive oligonucleotides of different lengths were obtained by partial pancreatic deoxyribonuclease digestion. From the characteristic mobilities of these oligonucleotides in two dimensional fractionation systems, the 3′ terminal sequence -ACCCGCG for the r-strand and -GGTTACG for the l-strand of λ DNA have been determined. In the second procedure, approximately six nucleotides were removed from each 3′ terminus with exonuclease III, and they were replaced with radioactive nucleotides by partial repair synthesis. After enzymatic digestion and sequence analysis, the above sequences have been confirmed. The 3′ terminal sequences in φ80 DNA are identical to those in λ DNA at least up to the fifth nucleotide from the 3′ ends.