title: Periodic acceptor excitation spectroscopy of single molecules.
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.
authors.affiliation: Clarendon Laboratory, Department of Physics and IRC in Bionanotechnology, Oxford University, Oxford, UK. sdoose@physik.uni-bielefeld.de
authors.forename: Sören
authors.initials: S
authors.lastname: Doose
authors.forename: Mike
authors.initials: M
authors.lastname: Heilemann
authors.forename: Xavier
authors.initials: X
authors.lastname: Michalet
authors.forename: Shimon
authors.initials: S
authors.lastname: Weiss
authors.forename: Achillefs N
authors.initials: AN
authors.lastname: Kapanidis
mesh_terms: D004247:DNA / Q000737:chemistry*; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods; D013057:Spectrum Analysis / Q000379:methods*
chemical_list: D004247:DNA