Purification in a functional form of the terminal protein of Bacillus subtilis phage phi 29

Proc Natl Acad Sci U S A. 1984 Mar;81(6):1639-43. doi: 10.1073/pnas.81.6.1639.


Phage phi 29 terminal protein, p3, essentially pure, was isolated in a denatured form from viral particles, and anti-p3 antiserum was obtained. A radioimmunoassay to detect and quantitate protein p3 was developed. By using this assay, native protein p3 was highly purified from Escherichia coli cells harboring a gene 3-containing recombinant plasmid. After three purification steps, the protein was more than 96% pure; its amino acid composition was very similar to that deduced from the nucleotide sequence of gene 3. The purified protein was active in the formation of the covalent p3-dAMP initiation complex when supplemented with extracts of B. subtilis infected with a sus mutant of phi 29 in gene 3. No DNA polymerase or ATPase activities were present in the final preparation of protein p3.

Publication types

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

MeSH terms

  • Bacillus subtilis
  • Bacteriophages / analysis*
  • Cloning, Molecular
  • DNA Replication*
  • Radioimmunoassay
  • Viral Proteins / immunology
  • Viral Proteins / isolation & purification*
  • Virus Replication*


  • Viral Proteins