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Updated: Jul 17, 2026

High Precision FRET at Single-molecule Level for Biomolecule Structure Determination
Published on: May 13, 2017
Periodic acceptor excitation spectroscopy of single molecules
Sören Doose1, Mike Heilemann, Xavier Michalet
1Clarendon Laboratory, Department of Physics and IRC in Bionanotechnology, Oxford University, Oxford, UK. sdoose@physik.uni-bielefeld.de
Abstract:
Alternating-laser excitation (ALEX) spectroscopy has recently been added to the single-molecule spectroscopy toolkit. ALEX monitors interaction and stoichiometry of biomolecules, reports on biomolecular structure by measuring accurate Förster resonance energy transfer (FRET) efficiencies, and allows sorting of subpopulations on the basis of stoichiometry and FRET. Here, we demonstrate that a simple combination of one continuous-wave donor-excitation laser and one directly modulated acceptor-excitation laser (Periodic Acceptor eXcitation) is sufficient to recapitulate the capabilities of ALEX while minimizing the cost and complexity associated with use of modulation techniques.
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