A dideoxynucleotide-sensitive DNA polymerase activity characterized from endoreduplicating cells of mungbean (Vigna radiata L.) during ontogeny of cotyledons

FEBS J. 2007 Apr;274(8):2005-23. doi: 10.1111/j.1742-4658.2007.05744.x. Epub 2007 Jan 12.


Within this work we describe the purification and biochemical characterization of a ddNTP-sensitive DNA polymerase purified from mungbean (Vigna radiata cv B1, L.) seeds at 18 days after fertilization, when > 70% of the nuclei are reported to be in the endoreduplicated state. The purified enzyme is a single polypeptide of 62 kDa and many of its physicochemical properties are similar to those of mammalian DNA polymerase beta. Similar to the other X-family DNA polymerases, it lacks 3'-5' exonuclease activity and has short gap-filling and strand-displacement activity. The enzyme shows moderately processive DNA synthesis on a single-strand template. The determined N-terminal heptapeptide sequence of the enzyme showed clear homology with helix 1 of the N-terminal single strand DNA-binding domain (residues 32-41) of rat and human DNA polymerase beta. These results represent the first evidence for the identification and characterization of a ddNTP-sensitive DNA polymerase expressed during the endoreduplication cycle that shares biochemical and immunological similarity with mammalian DNA polymerase beta.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cotyledon / growth & development*
  • DNA / biosynthesis
  • DNA Primers
  • DNA-Directed DNA Polymerase / chemistry
  • DNA-Directed DNA Polymerase / isolation & purification*
  • DNA-Directed DNA Polymerase / metabolism
  • Deoxyribonucleotides / pharmacology*
  • Fabaceae / enzymology*
  • Fabaceae / growth & development
  • Molecular Sequence Data
  • Molecular Weight
  • Nucleic Acid Synthesis Inhibitors
  • Rats


  • DNA Primers
  • Deoxyribonucleotides
  • Nucleic Acid Synthesis Inhibitors
  • DNA
  • DNA-Directed DNA Polymerase