The hydrophobic hinge region of rat DNA polymerase β is critical for substrate binding pocket geometry

Daniela Starcevic, Shibani Dalal, Joachim Jaeger, Joann B. Sweasy

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

The hydrophobic hinge of DNA polymerase β facilitates closing and stabilization of the enzyme once the nucleotide substrate has bound. Alteration of the hydrophobic nature of the hinge by the introduction of a hydrophilic glutamine residue in place of isoleucine 260 results in an inaccurate polymerase. The kinetic basis of infidelity is lack of discrimination during the binding of substrate. The I260Q polymerase β variant has lower affinity than wild type enzyme for the correct substrate and much higher affinity for the incorrect substrate. Our results demonstrate that the hinge is important for formation of the substrate binding pocket. Our results are also consistent with the interpretation that DNA polymerase β discriminates the correct from incorrect substrate during the binding step.

Original languageEnglish (US)
Pages (from-to)28388-28393
Number of pages6
JournalJournal of Biological Chemistry
Volume280
Issue number31
DOIs
StatePublished - Aug 5 2005
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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