title: DNA motion capture reveals the mechanical properties of DNA at the mesoscale.
abstract: Single-molecule studies probing the end-to-end extension of long DNAs have established that the mechanical properties of DNA are well described by a wormlike chain force law, a polymer model where persistence length is the only adjustable parameter. We present a DNA motion-capture technique in which DNA molecules are labeled with fluorescent quantum dots at specific sites along the DNA contour and their positions are imaged. Tracking these positions in time allows us to characterize how segments within a long DNA are extended by flow and how fluctuations within the molecule are correlated. Utilizing a linear response theory of small fluctuations, we extract elastic forces for the different, ∼2-μm-long segments along the DNA backbone. We find that the average force-extension behavior of the segments can be well described by a wormlike chain force law with an anomalously small persistence length.
authors.affiliation: Department of Chemistry and Physics, Emmanuel College, Boston, Massachusetts.
authors.forename: Allen C
authors.initials: AC
authors.lastname: Price
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado.
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Pilkiewicz
authors.affiliation: Department of Systems Biology, Harvard Medical School, Boston, Massachusetts; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts.
authors.forename: Thomas G W
authors.initials: TGW
authors.lastname: Graham
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts; Harvard Biophysics Program, Harvard Medical School, Boston, Massachusetts.
authors.forename: Dan
authors.initials: D
authors.lastname: Song
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado. Electronic address: joel.eaves@colorado.edu.
authors.forename: Joel D
authors.initials: JD
authors.lastname: Eaves
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts. Electronic address: joseph_loparo@hms.harvard.edu.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Loparo
mesh_terms: D004269:DNA, Bacterial / Q000737:chemistry*; D004548:Elasticity; D009038:Motion
chemical_list: D004269:DNA, Bacterial