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Soft Matter and Biological Physics
Eur. Phys. J. E 11, 105-108 (2003)
DOI: 10.1140/epje/i2002-10150-9

Transverse fluctuation analysis of single extended DNA molecules

Z. Gueroui, E. Freyssingeas, C. Place and B. Berge

Laboratoire de Physique (UMR CNRS 5672), Ecole Normale Superieure de Lyon, 46 Allée d'Italie, 69007 Lyon, France

zoherg@rockefeller.edu

(Received 11 November 2002 and Received in final form 5 March 2003 / Published online: 4 June 2003)

Abstract
We observed fluctuations of elongated DNA molecules by fluorescence microscopy. The molecules are fixed at both ends and undulate. Mode analysis of the thermally excited undulations of the labeled DNA molecules gives access to the spectral density of the amplitude fluctuations. From these measurements we estimate the tension acting on the DNA molecules. We found the forces to be within the entropic elasticity range of a typical DNA molecule (measured on the single-molecule level).

PACS
82.35.Pq - Biopolymers, biopolymerization.
87.15.Ya - Biomolecules: Fluctuations.
82.37.Rs - Single molecule manipulation of proteins and other biological molecules.

© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2003