Effects of internal deletions on the priming activity of the phage phi 29 terminal protein

Gene. 1989 Nov 30;83(2):187-95. doi: 10.1016/0378-1119(89)90104-2.


A series of internal deletions of gene 3, coding for the phage phi 29 DNA terminal protein, have been constructed and characterized. In addition, a substitution mutant in the sequence corresponding to amino acids (aa) 49-51 was obtained. The priming activity of the substitution mutant protein, in the formation of the protein p3-dAMP initiation complex, was drastically reduced suggesting that some of the aa present at position 49-51 are essential for p3 function. Deletions of 8 to 33 aa, from aa residue 48 towards the N terminus of the substitution mutant, further decreased the priming activity of the protein. The activity of deletion mutants lacking 15 or 21 aa from residue 57 towards the C terminus, and also containing a point mutation at position 56, was greatly reduced, and no activity was seen when 24 aa were lacking.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Bacillus subtilis / genetics*
  • Bacteriophages / genetics*
  • Base Sequence
  • Chromosome Deletion*
  • Cloning, Molecular
  • Escherichia coli / genetics
  • Genes, Viral*
  • Molecular Sequence Data
  • Mutation
  • Oligonucleotide Probes
  • Plasmids
  • Promoter Regions, Genetic
  • Viral Proteins / biosynthesis
  • Viral Proteins / genetics*
  • Viral Structural Proteins / genetics*


  • Oligonucleotide Probes
  • Viral Proteins
  • Viral Structural Proteins
  • p3 protein, bacteriophage phi 29