Super-resolution optical DNA Mapping via DNA methyltransferase-directed click chemistry

Research output: Contribution to journalArticlepeer-review


  • Charlotte Vranken
  • Jochem Deen
  • Lieve Dirix
  • Tim Stakenborg
  • Wim Dehaen
  • Volker Leen
  • Johan Hofkens

Colleges, School and Institutes

External organisations

  • Catholic University of Leuven
  • Life Science Technologies
  • University of Copenhagen


We demonstrate an approach to optical DNA mapping, which enables near single-molecule characterization of whole bacteriophage genomes. Our approach uses a DNA methyltransferase enzyme to target labelling to specific sites and copper-catalysed azide-alkyne cycloaddition to couple a fluorophore to the DNA. We achieve a labelling efficiency of ∼70% with an average labelling density approaching one site every 500 bp. Such labelling density bridges the gap between the output of a typical DNA sequencing experiment and the long-range information derived from traditional optical DNA mapping. We lay the foundations for a wider-scale adoption of DNA mapping by screening 11 methyltransferases for their ability to direct sequence-specific DNA transalkylation; the first step of the DNA labelling process and by optimizing reaction conditions for fluorophore coupling via a click reaction. Three of 11 enzymes transalkylate DNA with the cofactor we tested (a readily prepared s-adenosyl-l-methionine analogue).


Original languageEnglish
Article numbere50
JournalNucleic Acids Research
Issue number7
Early online date21 Jan 2014
Publication statusPublished - 2014

ASJC Scopus subject areas