Cloning and DNA sequence of the 5'‐exonuclease gene of bacteriophage T5

The nucleotide sequence of the BalI-PstI fragment of T5 DNA, 1347 bp in length, coding for 5'-exonuclease (D15 gene), has been determined. A coding region of the gene contains 873 bp and is preceded by a typical Shine-Dalgarno sequence. The D15 gene belongs to a cluster, consisting of at least 3 genes, in which a termination codon of a preceding gene overlaps an initiation codon of the following one. The sequence contains an open reading frame for 291 amino acid residues. The molecular mass of the 5'-exonuclease calculated from the predicted amino acid sequence is 33 400 Da.