A 43 kDa DNA binding protein from the pea chloroplast interacts with and stimulates the cognate DNA polymerase

Nucleic Acids Res. 1996 Oct 15;24(20):3953-61. doi: 10.1093/nar/24.20.3953.


A DNA binding protein with DNA polymerase 'accessory activity' has been identified and purified to apparent homogeneity from pea chloroplasts. This protein consists of a single subunit of 43 kDa and binds to DNA regardless of its base sequence and topology. It increases cognate DNA polymerase-primase activity in a dose dependent manner. Using solid phase protein-protein interaction trapping and co-immunoprecipitation techniques, the purified protein was found to associate with the chloroplast DNA polymerase. The chloroplast DNA polymerase also binds directly to the radioiodinated 43 kDa protein. The specific interaction between 43 kDa protein and chloroplast DNA polymerase results in the synthesis of longer DNA chains. The 43 kDa protein, present abundantly in the pea chloroplast, appears to increase processivity of the chloroplast DNA polymerase and may play an important role in the replication of pea chloroplast DNA.

MeSH terms

  • Antibodies / immunology
  • Antibodies / metabolism
  • Blotting, Western
  • Chloroplasts / chemistry
  • Chloroplasts / enzymology*
  • DNA / biosynthesis
  • DNA / metabolism
  • DNA-Binding Proteins / chemistry*
  • DNA-Binding Proteins / isolation & purification
  • DNA-Binding Proteins / metabolism
  • DNA-Directed DNA Polymerase / chemistry
  • DNA-Directed DNA Polymerase / metabolism*
  • Electrophoresis, Agar Gel
  • Electrophoresis, Polyacrylamide Gel
  • Enzyme Activation
  • Microscopy, Electron
  • Pisum sativum / metabolism
  • Plant Proteins / chemistry
  • Plant Proteins / isolation & purification
  • Plant Proteins / metabolism
  • Precipitin Tests


  • Antibodies
  • DNA-Binding Proteins
  • Plant Proteins
  • DNA
  • DNA-Directed DNA Polymerase