Mismatch-specific 3'----5' exonuclease associated with the mitochondrial DNA polymerase from Drosophila embryos.
AUTOR(ES)
Kaguni, L S
RESUMO
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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=297865Documentos Relacionados
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