Staphylococcus aureus DinG, a helicase that has evolved into a nuclease

Anne Marie McRobbie, Bjoern Meyer, Christophe Rouillon, Biljana Petrovic-Stojanovska, Huanting Liu, Malcolm F. White

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

DinG (damage inducible gene G) is a bacterial superfamily 2 helicase with 5′→3′ polarity. DinG is related to the XPD (xeroderma pigmentosum complementation group D) helicase family, and they have in common an FeS (iron-sulfur)-binding domain that is essential for the helicase activity. In the bacilli and clostridia, the DinG helicase has become fusedwith an N-terminal domain that is predicted to be an exonuclease. In the present paper we show that the DinG protein from Staphylococcus aureus lacks an FeS domain and is not a DNA helicase, although it retains DNA-dependent ATP hydrolysis activity. Instead, the enzyme is an active 3′→5′ exonuclease acting on single-stranded DNA and RNA substrates. The nuclease activity can be modulated by mutation of the ATP-binding cleft of the helicase domain, and is inhibited by ATP or ADP, suggesting a modified role for the inactive helicase domain in the control of the nuclease activity. By degrading rather than displacing RNA or DNA strands, the S. aureus DinG nuclease may accomplish the same function as the canonical DinG helicase.

Original languageEnglish (US)
Pages (from-to)77-84
Number of pages8
JournalBiochemical Journal
Volume442
Issue number1
DOIs
StatePublished - Feb 15 2012

Keywords

  • DNA repair
  • Damage inducible gene G (DinG)
  • Helicase
  • Iron-sulfur
  • Nuclease
  • Xeroderma pigmentosum complementation group D (XPD)

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