Kinetic measurement of the step size of DNA unwinding by Escherichia coli UvrD helicase

Janid A. Ali, Timothy M. Lohman

Research output: Contribution to journalArticle

217 Scopus citations

Abstract

The kinetic mechanism by which the DNA repair helicase UvrD of Escherichia coli unwinds duplex DNA was examined with the use of a series of oligodeoxynucleotides with duplex regions ranging from 10 to 40 base pairs. Single-turnover unwinding experiments showed distinct lag phases that increased with duplex length because partially unwound DNA intermediate states are highly populated during unwinding. Analysis of these kinetics indicates that UvrD unwinds duplex DNA in discrete steps, with an average 'step size' of 4 to 5 base pairs (approximately one-half turn of the DNA helix). This suggests an unwinding mechanism in which alternating subunits of the dimeric helicase interact directly with duplex DNA.

Original languageEnglish
Pages (from-to)377-380
Number of pages4
JournalScience
Volume275
Issue number5298
DOIs
StatePublished - Jan 17 1997

Fingerprint Dive into the research topics of 'Kinetic measurement of the step size of DNA unwinding by Escherichia coli UvrD helicase'. Together they form a unique fingerprint.

  • Cite this