Formation of a covalent complex between the terminal protein of pneumococcal bacteriophage Cp-1 and 5'-dAMP

J Virol. 1986 Apr;58(1):31-5. doi: 10.1128/JVI.58.1.31-35.1986.


Incubation of extracts of Cp-1-infected Streptococcus pneumoniae with [alpha-32P]dATP produced a labeled treatment with micrococcal nuclease and sensitive to treatment with proteinase K. Incubation of the 32P-labeled protein with 5 M piperidine for 4 h at 50 degrees C released 5'-dAMP, indicating that a covalent complex between the terminal protein and 5'-dAMP was formed in vitro. When the four deoxynucleoside triphosphates were included in the reaction mixture, a labeled complex of slower electrophoretic mobility in sodium dodecyl sulfate-polyacrylamide gels than the terminal protein-dAMP complex was also found, indicating that the Cp-1 terminal protein-dAMP complex can be elongated and, therefore, that it is an initiation complex. Treatment of the 32P-labeled terminal protein-dAMP complex with 5.8 M HCl at 110 degrees C for 2 h yielded phosphothreonine. These results, together with the resistance of the terminal protein-DNA linkage to hydroxylamine, suggest that the Cp-1 terminal protein is covalently linked to the DNA through a phosphoester bond between L-threonine and 5'-dAMP, namely, a O-5'-deoxyadenylyl-L-threonine bond.

Publication types

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

MeSH terms

  • Bacteriophages / genetics*
  • Bacteriophages / metabolism
  • DNA Replication*
  • DNA, Viral / biosynthesis
  • DNA-Binding Proteins / metabolism*
  • Deoxyadenine Nucleotides / metabolism*
  • Streptococcus pneumoniae*
  • Threonine / metabolism
  • Viral Proteins / metabolism*
  • Virus Replication*


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