Site-directed mutagenesis in the DNA linking site of bacteriophage phi 29 terminal protein: isolation and characterization of a Ser232----Thr mutant

Nucleic Acids Res. 1988 Jul 11;16(13):5727-40. doi: 10.1093/nar/16.13.5727.


By site-directed mutagenesis we have changed the serine residue 232 of the phi 29 terminal protein, involved in the covalent linkage to dAMP for the initiation of replication, into a threonine residue. The mutant terminal protein has been purified to homogeneity and shown to be inactive in the formation of the initiation complex; nevertheless, the mutant protein retains its ability to interact with the phi 29 DNA polymerase and with the DNA. The results obtained indicate a high specificity in the linking site of the terminal protein.

Publication types

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

MeSH terms

  • Bacteriophages / genetics*
  • DNA, Viral / metabolism*
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Mutation*
  • Plasmids
  • Serine
  • Threonine
  • Viral Proteins / genetics*
  • Viral Proteins / metabolism


  • DNA, Viral
  • DNA-Binding Proteins
  • Viral Proteins
  • terminal protein, Streptococcus phage Cp-1
  • Threonine
  • Serine