title: Nanometal surface energy transfer in optical rulers, breaking the FRET barrier.
abstract: Optical-based distance measurements are essential for tracking biomolecular conformational changes, drug discovery, and cell biology. Traditional Forster resonance energy transfer (FRET) is efficient for separation distances up to 100 A. We report the first successful application of a dipole-surface type energy transfer from a molecular dipole to a nanometal surface that more than doubles the traditional Forster range (220 A) and follows a 1/R(4) distance dependence. We appended a 1.4 nm Au cluster to the 5' end of one DNA strand as the energy acceptor and a fluorescein (FAM) to the 5' end of the complementary strand as the energy donor. Analysis of the energy transfer on DNA lengths (15, 20, 30, 60bp), complemented by protein-induced DNA bending, provides the basis for fully mapping the extent of this dipole surface type mechanism over its entire usable range (50-250 A). Further, protein function is fully compatible with these nanometal-DNA constructs. Significantly extending the range of optical based methods in molecular rulers is an important leap forward for biophysics.
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, USA.
authors.forename: C S
authors.initials: CS
authors.lastname: Yun
authors.forename: A
authors.initials: A
authors.lastname: Javier
authors.forename: T
authors.initials: T
authors.lastname: Jennings
authors.forename: M
authors.initials: M
authors.lastname: Fisher
authors.forename: S
authors.initials: S
authors.lastname: Hira
authors.forename: S
authors.initials: S
authors.lastname: Peterson
authors.forename: B
authors.initials: B
authors.lastname: Hopkins
authors.forename: N O
authors.initials: NO
authors.lastname: Reich
authors.forename: G F
authors.initials: GF
authors.lastname: Strouse
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D015246:Deoxyribonuclease EcoRI / Q000737:chemistry / Q000378:metabolism; D019793:Fluorescein / Q000737:chemistry*; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D036103:Nanotechnology / Q000379:methods*; D013499:Surface Properties
chemical_list: D005456:Fluorescent Dyes; D006046:Gold; D004247:DNA; D015246:Deoxyribonuclease EcoRI; D019793:Fluorescein