Defining the roles of individual residues in the single-stranded DNA binding site of PcrA helicase

M S Dillingham, P Soultanas, P Wiley, M R Webb, D B Wigley

Research output: Contribution to journalArticle (Academic Journal)peer-review

70 Citations (Scopus)

Abstract

Crystal structures and biochemical analyses of PcrA helicase provide evidence for a model for processive DNA unwinding that involves coupling of single-stranded DNA (ssDNA) tracking to a duplex destabilization activity. The DNA tracking model invokes ATP-dependent flipping of bases between several pockets on the enzyme formed by conserved aromatic amino acid residues. We have used site-directed mutagenesis to confirm the requirement of all of these residues for helicase activity. We also demonstrate that the duplex unwinding defects correlate with an inability of certain mutant proteins to translocate effectively on ssDNA. Moreover, the results define an essential triad of residues within the ssDNA binding site that comprise the ATP-driven DNA motor itself.
Translated title of the contributionDefining the roles of individual residues in the single-stranded DNA binding site of PcrA helicase
Original languageEnglish
Pages (from-to)8381 - 8387
Number of pages7
JournalProceedings of the National Academy of Sciences of the United States of America
Volume98
Issue number15
DOIs
Publication statusPublished - Jul 2001

Bibliographical note

Publisher: National Academy of Sciences

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