Open AccessMismatch-specific 3'----5' exonuclease associated with the mitochondrial DNA polymerase from Drosophila embryos.
Author(s) -
Laurie S. Kaguni,
Matthew W. Olson
Publication year - 1989
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.86.17.6469
Subject(s) - klenow fragment , dna polymerase , biology , exonuclease , primer (cosmetics) , dna polymerase ii , dna replication , primase , polymerase , dna , dna clamp , mitochondrial dna , microbiology and biotechnology , dna polymerase i , proofreading , biochemistry , genetics , polymerase chain reaction , gene , chemistry , reverse transcriptase , organic chemistry
The mitochondrial DNA polymerase from Drosophila embryos lacks dNTP turnover activity. However, a potent 3'----5' exonuclease activity can be detected by a specific assay in which the exonuclease excises mispaired nucleotides at the 3' termini of primed synthetic and natural DNA templates. The excision of a mispaired nucleotide occurs at a significantly greater rate than excision of a correctly paired nucleotide and, under conditions of DNA synthesis, hydrolysis of a mispaired terminal nucleotide occurs prior to primer extension. The 3'----5' exonuclease copurifies quantitatively with DNA polymerase gamma and cosediments with the nearly homogeneous enzyme under native conditions. These results suggest that the 3'----5' exonuclease provides a proofreading function to enhance the fidelity of DNA synthesis during Drosophila mitochondrial DNA replication.