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Mechanical Properties of Single Motor Molecules Studied by Three‐Dimensional Thermal Force Probing in Optical Tweezers
Author(s) -
Jeney Sylvia,
Stelzer Ernst H. K.,
Grubmüller Helmut,
Florin ErnstLudwig
Publication year - 2004
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200301027
Subject(s) - optical tweezers , kinesin , molecular motor , brownian motion , molecule , molecular physics , chemical physics , chemistry , thermal fluctuations , thermal , motor protein , nanotechnology , physics , materials science , optics , microtubule , condensed matter physics , thermodynamics , quantum mechanics , organic chemistry , biology , microbiology and biotechnology
Abstract A new method combining three‐dimensional (3D) force measurements in an optical trap with the analysis of thermally induced (Brownian) position fluctuations of a trapped probe was used to investigate the mechanical properties of a single molecule, the molecular motor kinesin. One kinesin molecule attached to the probe was bound in a rigorlike state to one microtubule. The optical trap was kept weak to measure the thermal forces acting on the probe, which were mainly counterbalanced by the kinesin tether. The stiffness of kinesin during stretching and compression with respect to its backbone axis were measured. Our results indicate that a section of kinesin close to the motor domain is the dominating element in the flexibility of the motor structure. The experiments demonstrate the power of 3D thermal fluctuation analysis to characterize mechanical properties of individual motor proteins and indicate its usefulness to study single molecule in general.