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Nat Methods. 2011 Apr;8(4):335-40. doi: 10.1038/nmeth.1574. Epub 2011 Feb 20.

Ultrahigh-resolution optical trap with single-fluorophore sensitivity.

Author information

1
Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.

Abstract

We present a single-molecule instrument that combines a time-shared ultrahigh-resolution dual optical trap interlaced with a confocal fluorescence microscope. In a demonstration experiment, we observed individual single fluorophore-labeled DNA oligonucleotides to bind and unbind complementary DNA suspended between two trapped beads. Simultaneous with the single-fluorophore detection, we clearly observed coincident angstrom-scale changes in tether extension. Fluorescence readout allowed us to determine the duplex melting rate as a function of force. The new instrument will enable the simultaneous measurement of angstrom-scale mechanical motion of individual DNA-binding proteins (for example, single-base-pair stepping of DNA translocases) along with the detection of properties of fluorescently labeled protein (for example, internal configuration).

PMID:
21336286
PMCID:
PMC3732480
DOI:
10.1038/nmeth.1574
[Indexed for MEDLINE]
Free PMC Article

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