Kinesin motion in the absence of external forces characterized by interference total internal reflection microscopy.

Physico Chimie Curie, UMR CNRS/IC 168, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
Physical Review E (Impact Factor: 2.33). 09/2003; 68(2 Pt 1):021907. DOI: 10.1103/PhysRevE.68.021907
Source: PubMed

ABSTRACT We study the motion of the kinesin molecular motor along microtubules using interference total internal reflection microscopy. This technique achieves nanometer scale resolution together with a fast time response. We describe the first in vitro observation of kinesin stepping at high ATP concentration in the absence of an external load, where the 8-nm step can be clearly distinguished. The short-time resolution allows us to measure the time constant related to the relative motion of the bead-motor connection; we deduce the associated bead-motor elastic modulus.

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