DNA Structure Specificity Conferred on a Replicative Helicase by Its Loader

Milind Kumar Gupta, John David Atkinson, Peter McGlynn

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Prokaryotic and eukaryotic replicative helicases can translocate along single-stranded and double-stranded DNA, with the central cavity of these multimeric ring helicases being able to accommodate both forms of DNA. Translocation by such helicases along single-stranded DNA results in the unwinding of forked DNA by steric exclusion and appears critical in unwinding of parental strands at the replication fork, whereas translocation over double-stranded DNA has no well-defined role. We have found that the accessory factor, DnaC, that promotes loading of the Escherichia coli replicative helicase DnaB onto single-stranded DNA may also act to confer DNA structure specificity on DnaB helicase. When present in excess, DnaC inhibits DnaB translocation over double-stranded DNA but not over single-stranded DNA. Inhibition of DnaB translocation over double-stranded DNA requires the ATP-bound form of DnaC, and this inhibition is relieved during translocation over single-stranded DNA indicating that stimulation of DnaC ATPase is responsible for this DNA structure specificity. These findings demonstrate that DnaC may provide the DNA structure specificity lacking in DnaB, limiting DnaB translocation to bona fide replication forks. The ability of other replicative helicases to translocate along single-stranded and double-stranded DNA raises the possibility that analogous regulatory mechanisms exist in other organisms.

Original languageEnglish
Pages (from-to)979-987
Number of pages9
JournalThe Journal of Biological Chemistry
Volume285
Issue number2
Early online date30 Oct 2009
DOIs
Publication statusPublished - 8 Jan 2010

Keywords

  • escherichia-coli DNAB
  • Double-straneded DNA
  • gene-product
  • hexameric helicase
  • protein complex
  • nucleotide cofactors
  • physical-properties
  • in-vitro
  • mechanism
  • fork

Cite this

DNA Structure Specificity Conferred on a Replicative Helicase by Its Loader. / Gupta, Milind Kumar; Atkinson, John David; McGlynn, Peter.

In: The Journal of Biological Chemistry, Vol. 285, No. 2, 08.01.2010, p. 979-987.

Research output: Contribution to journalArticle

Gupta, Milind Kumar ; Atkinson, John David ; McGlynn, Peter. / DNA Structure Specificity Conferred on a Replicative Helicase by Its Loader. In: The Journal of Biological Chemistry. 2010 ; Vol. 285, No. 2. pp. 979-987.
@article{dd3ccc92a702428582b25e9093f4ee56,
title = "DNA Structure Specificity Conferred on a Replicative Helicase by Its Loader",
abstract = "Prokaryotic and eukaryotic replicative helicases can translocate along single-stranded and double-stranded DNA, with the central cavity of these multimeric ring helicases being able to accommodate both forms of DNA. Translocation by such helicases along single-stranded DNA results in the unwinding of forked DNA by steric exclusion and appears critical in unwinding of parental strands at the replication fork, whereas translocation over double-stranded DNA has no well-defined role. We have found that the accessory factor, DnaC, that promotes loading of the Escherichia coli replicative helicase DnaB onto single-stranded DNA may also act to confer DNA structure specificity on DnaB helicase. When present in excess, DnaC inhibits DnaB translocation over double-stranded DNA but not over single-stranded DNA. Inhibition of DnaB translocation over double-stranded DNA requires the ATP-bound form of DnaC, and this inhibition is relieved during translocation over single-stranded DNA indicating that stimulation of DnaC ATPase is responsible for this DNA structure specificity. These findings demonstrate that DnaC may provide the DNA structure specificity lacking in DnaB, limiting DnaB translocation to bona fide replication forks. The ability of other replicative helicases to translocate along single-stranded and double-stranded DNA raises the possibility that analogous regulatory mechanisms exist in other organisms.",
keywords = "escherichia-coli DNAB, Double-straneded DNA, gene-product, hexameric helicase, protein complex, nucleotide cofactors, physical-properties, in-vitro, mechanism, fork",
author = "Gupta, {Milind Kumar} and Atkinson, {John David} and Peter McGlynn",
year = "2010",
month = "1",
day = "8",
doi = "10.1074/jbc.M109.072520",
language = "English",
volume = "285",
pages = "979--987",
journal = "The Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC",
number = "2",

}

TY - JOUR

T1 - DNA Structure Specificity Conferred on a Replicative Helicase by Its Loader

AU - Gupta, Milind Kumar

AU - Atkinson, John David

AU - McGlynn, Peter

PY - 2010/1/8

Y1 - 2010/1/8

N2 - Prokaryotic and eukaryotic replicative helicases can translocate along single-stranded and double-stranded DNA, with the central cavity of these multimeric ring helicases being able to accommodate both forms of DNA. Translocation by such helicases along single-stranded DNA results in the unwinding of forked DNA by steric exclusion and appears critical in unwinding of parental strands at the replication fork, whereas translocation over double-stranded DNA has no well-defined role. We have found that the accessory factor, DnaC, that promotes loading of the Escherichia coli replicative helicase DnaB onto single-stranded DNA may also act to confer DNA structure specificity on DnaB helicase. When present in excess, DnaC inhibits DnaB translocation over double-stranded DNA but not over single-stranded DNA. Inhibition of DnaB translocation over double-stranded DNA requires the ATP-bound form of DnaC, and this inhibition is relieved during translocation over single-stranded DNA indicating that stimulation of DnaC ATPase is responsible for this DNA structure specificity. These findings demonstrate that DnaC may provide the DNA structure specificity lacking in DnaB, limiting DnaB translocation to bona fide replication forks. The ability of other replicative helicases to translocate along single-stranded and double-stranded DNA raises the possibility that analogous regulatory mechanisms exist in other organisms.

AB - Prokaryotic and eukaryotic replicative helicases can translocate along single-stranded and double-stranded DNA, with the central cavity of these multimeric ring helicases being able to accommodate both forms of DNA. Translocation by such helicases along single-stranded DNA results in the unwinding of forked DNA by steric exclusion and appears critical in unwinding of parental strands at the replication fork, whereas translocation over double-stranded DNA has no well-defined role. We have found that the accessory factor, DnaC, that promotes loading of the Escherichia coli replicative helicase DnaB onto single-stranded DNA may also act to confer DNA structure specificity on DnaB helicase. When present in excess, DnaC inhibits DnaB translocation over double-stranded DNA but not over single-stranded DNA. Inhibition of DnaB translocation over double-stranded DNA requires the ATP-bound form of DnaC, and this inhibition is relieved during translocation over single-stranded DNA indicating that stimulation of DnaC ATPase is responsible for this DNA structure specificity. These findings demonstrate that DnaC may provide the DNA structure specificity lacking in DnaB, limiting DnaB translocation to bona fide replication forks. The ability of other replicative helicases to translocate along single-stranded and double-stranded DNA raises the possibility that analogous regulatory mechanisms exist in other organisms.

KW - escherichia-coli DNAB

KW - Double-straneded DNA

KW - gene-product

KW - hexameric helicase

KW - protein complex

KW - nucleotide cofactors

KW - physical-properties

KW - in-vitro

KW - mechanism

KW - fork

U2 - 10.1074/jbc.M109.072520

DO - 10.1074/jbc.M109.072520

M3 - Article

VL - 285

SP - 979

EP - 987

JO - The Journal of Biological Chemistry

JF - The Journal of Biological Chemistry

SN - 0021-9258

IS - 2

ER -