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

作者：Valerie Mizrahi, Patricia A. Benkovic, Stephen J. Benkovic · 发表于：Proceedings of the National Academy of Sciences · 年份：1986 · DOI：10.1073/pnas.83.16.5769 · 被引用次数：55 · 研究领域：Protein Structure and Dynamics、DNA and Nucleic Acid Chemistry、Bacterial Genetics and Biotechnology

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.