Single-molecule Fluorescence Spectroscopy of TOTO on Poly-AT and Poly-GC DNA

Benjamin P. Bowen, Jörg Enderlein, Neal Woodbury

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Excited state lifetime and amplitude measurements were made on thiazole orange dimer (TOTO), a dimeric DNA-intercalating fluorophore, at single-molecule concentrations. As expected from previous study, the excited state lifetime of TOTO intercalated in DNA is dependent on the sequence of the double-stranded DNA, having values of 2.2 ns in poly-GC DNA and 1.8 ns in poly-AT DNA. The distribution of excited state lifetimes of single molecules of TOTO intercalated into oligonucleotides having varying proportions of poly-GC sequences relative to poly-AT sequences were analyzed as a function of the fraction of poly-GC. By using excited state lifetime distributions from the purely GC and purely AT oligonucleotides as a basis set, it was possible to estimate the GC content of oligonucleotides with intermediate GC composition to within a few percent error. This serves as a model for the analysis of equilibrium binding distributions in DNA using single-molecule methods.

Original languageEnglish (US)
Pages (from-to)576-581
Number of pages6
JournalPhotochemistry and photobiology
Volume78
Issue number6
DOIs
StatePublished - Dec 1 2003

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry

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