Subtle but variable conformational rearrangements in the replication cycle of Sulfolobus solfataricus P2 DNA polymerase IV (Dpo4) may accommodate lesion bypass

Yanli Wang, Karunesh Arora, Tamar Schlick

Research output: Contribution to journalArticle

Abstract

The possible conformational changes of DNA polymerase IV (Dpo4) before and after the nucleotidyltransfer reaction are investigated at the atomic level by dynamics simulations to gain insight into the mechanism of low-fidelity polymerases and identify slow and possibly critical steps. The absence of significant conformational changes in Dpo4 before chemistry when the incoming nucleotide is removed supports the notion that the "induced-fit" mechanism employed to interpret fidelity in some replicative and repair DNA polymerases does not exist in Dpo4. However, significant correlated movements in the little finger and finger domains, as well as DNA sliding and subtle catalytic-residue rearrangements, occur after the chemical reaction when both active-site metal ions are released. Subsequently, Dpo4's little finger grips the DNA through two arginine residues and pushes it forward. These metal ion correlated movements may define subtle, and possibly characteristic, conformational adjustments that operate in some Y-family polymerase members in lieu of the prominent subdomain motions required for catalytic cycling in other DNA polymerases like polymerase β. Such subtle changes do not easily provide a tight fit for correct incoming substrates as in higher-fidelity polymerases, but introduce in low-fidelity polymerases different fidelity checks as well as the variable conformational-mobility potential required to bypass different lesions. Published by Cold Spring Harbor Laboratory Press.

Original languageEnglish (US)
Pages (from-to)135-151
Number of pages17
JournalProtein Science
Volume15
Issue number1
DOIs
StatePublished - Jan 2006

Keywords

  • Catalytic metal ion
  • Conformational changes
  • Dpo4
  • Dynamics simulations
  • Nucleotide-binding metal ion
  • Replication mechanism

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology

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