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Proc Natl Acad Sci U S A. 1986 Aug;83(16):5769-73.

Mechanism of DNA polymerase I: exonuclease/polymerase activity switch and DNA sequence dependence of pyrophosphorolysis and misincorporation reactions.

Abstract

Mechanistic features of several processes involved in the idling-turnover reaction catalyzed by the large (Klenow) fragment of Escherichia coli DNA polymerase I have been established. The exonuclease----polymerase activity switch involved in the excision/incorporation mode of idling-turnover occurs without an intervening dissociation of the enzyme from its DNA substrate. Comparative studies on the pyrophosphorolysis kinetics of related DNA substrates indicate a significant dependence of the reaction rate upon the DNA sequence within the duplex region upstream of the primer-template junction. Finally, a gel electrophoretic analysis of the products of the idling-turnover reaction has provided direct evidence for an alternative DNA sequence-dependent misincorporation/excision pathway.

PMID:
3016719
PMCID:
PMC386376
DOI:
10.1073/pnas.83.16.5769
[Indexed for MEDLINE]
Free PMC Article

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