Berlin 2012 – scientific programme
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BP: Fachverband Biologische Physik
BP 25: Posters: Molecular Motors
BP 25.4: Poster
Thursday, March 29, 2012, 17:30–19:30, Poster A
Nanometer precision in filament localization allows for precise off-axis tracking of molecular motors — •Felix Ruhnow1,2, David Zwicker3, and Stefan Diez1,2 — 1B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Dresden, Germany — 2Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany — 3Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
Measuring the exact path of molecular motors, such as cytoskeletal motor proteins, on their tracks has proven to be difficult without knowing the precise location of the filaments. Up to now, off-axis stepping has therefore mostly been inferred from the tracked positions of the motors with respect to the fitted path of the motors instead of determining the filament centerline. Obviously, this limits the precision of the measurements and may lead to errors due to the sometimes complex three-dimensional structure of the filaments. We developed a filament tracking algorithm to determine the centerline position of fluorescently labeled filaments with nanometer precision. This allowed us to observe the non-parallel movement of kinesin-1 motors with respect to the microtubule centerline, which is consistent with kinesin-1 following a protofilament of a supertwisted microtubule. Combined with methods to measure nanometer heights above substrate surfaces, such as fluorescence interference contrast or parallax, our algorithm presents a promising tool for optical 3D-nanometry.