Recognition and manipulation of branched DNA structure by junction-resolving enzymes

Malcolm F White, M J E GiraudPanis, J R G Pohler, D M J Lilley

Research output: Contribution to journalReview articlepeer-review

93 Citations (Scopus)

Abstract

The junction-resolving enzymes are a class of nucleases that introduce paired cleavages into four-way DNA junctions. They are important in DNA recombination and repair, and are found throughout nature, from eubacteria and their bacteriophages through to higher eukaryotes and their viruses. These enzymes exhibit structure-selective binding to DNA junctions; although cleavage may be more or less sequence-dependent, binding affinity is purely related to the branched structure of the DNA. Binding and cleavage events can be separated for a number of the enzymes by mutagenesis, and mutant proteins that are defective in cleavage while retaining normal junction-selective binding have been isolated. Critical acidic residues have been identified in several resolving enzymes, suggesting a role in the coordination of metal ions that probably deliver the hydrolytic water molecule. The resolving enzymes all bind to junctions in dimeric form, and the subunits introduce independent cleavages within the lifetime of the enzyme-junction complex to ensure resolution of the four-way junction. In addition to recognising the structure of the junction, recent data from four different junction-resolving enzymes indicate that they also manipulate the global structure. In some cases this results in severe distortion of the folded structure of the junction. Understanding the recognition and manipulation of DNA structure by these enzymes is a fascinating challenge in molecular recognition. (C) 1997 Academic Press Limited.

Original languageEnglish
Pages (from-to)647-664
Number of pages18
JournalJournal of Molecular Biology
Volume269
Issue number5
Publication statusPublished - 27 Jun 1997

Keywords

  • recombination
  • nucleases
  • DNA-protein interaction
  • DNA structure
  • ESCHERICHIA-COLI RUVA
  • SYNTHETIC HOLLIDAY JUNCTIONS
  • SITE-SPECIFIC RECOMBINATION
  • T4 ENDONUCLEASE-VII
  • RESONANCE ENERGY-TRANSFER
  • FAST SEDIMENTING DNA
  • GENETIC-RECOMBINATION
  • SACCHAROMYCES-CEREVISIAE
  • SUPERCOILED DNA
  • 4-WAY JUNCTION

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