The highly conserved amino acid sequence motif Tyr-Gly-Asp-Thr-Asp-Ser in alpha-like DNA polymerases is required by phage phi 29 DNA polymerase for protein-primed initiation and polymerization

Proc Natl Acad Sci U S A. 1990 Jun;87(12):4610-4. doi: 10.1073/pnas.87.12.4610.


The alpha-like DNA polymerases from bacteriophage phi 29 and other viruses, prokaryotes and eukaryotes contain an amino acid consensus sequence that has been proposed to form part of the dNTP binding site. We have used site-directed mutants to study five of the six highly conserved consecutive amino acids corresponding to the most conserved C-terminal segment (Tyr-Gly-Asp-Thr-Asp-Ser). Our results indicate that in phi 29 DNA polymerase this consensus sequence, although irrelevant for the 3'----5' exonuclease activity, is essential for initiation and elongation. Based on these results and on its homology with known or putative metal-binding amino acid sequences, we propose that in phi 29 DNA polymerase the Tyr-Gly-Asp-Thr-Asp-Ser consensus motif is part of the dNTP binding site, involved in the synthetic activities of the polymerase (i.e., initiation and polymerization), and that it is involved particularly in the metal binding associated with the dNTP site.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Coliphages / enzymology*
  • DNA Polymerase II / genetics*
  • DNA Polymerase II / metabolism
  • DNA Replication
  • DNA-Directed DNA Polymerase / genetics*
  • DNA-Directed DNA Polymerase / metabolism
  • Escherichia coli / enzymology*
  • Exodeoxyribonuclease V
  • Exodeoxyribonucleases / metabolism
  • Kinetics
  • Molecular Sequence Data
  • Mutation
  • Sequence Homology, Nucleic Acid


  • DNA Polymerase II
  • DNA-Directed DNA Polymerase
  • Exodeoxyribonucleases
  • Exodeoxyribonuclease V