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A dideoxynucleotide‐sensitive DNA polymerase activity characterized from endoreduplicating cells of mungbean ( Vigna radiata L.) during ontogeny of cotyledons
Author(s) -
Roy Sujit,
Sarkar Sailendra Nath,
Singh Sanjay K.,
Sengupta Dibyendu N.
Publication year - 2007
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2007.05744.x
Subject(s) - dna polymerase , biology , dna clamp , microbiology and biotechnology , polymerase , dna polymerase ii , biochemistry , dna , primase , dna polymerase mu , polymerase chain reaction , circular bacterial chromosome , reverse transcriptase , gene
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 β. 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 β. 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 β.