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BP: Fachverband Biologische Physik

BP 31: Posters: Biological Machines \& Motor Proteins

BP 31.4: Poster

Thursday, March 17, 2011, 17:15–20:00, P3

A tetrameric chimera made from a kinesin-1 and a kinesin-5 shows interesting motility properties — •Alok D. Weßel, Christina Thiede, Stefan Lakämper, Stefanie Reiter, and Christoph F. Schmidt — Drittes Physikalisches Institut, Georg-August-Universität Göttingen, Germany

X. laevis Eg5 is a mitotic kinesin-5 that drives relative sliding of anti-parallel microtubules (MT) by the processive action of its two opposing sets of dimeric motors. In order to obtain a tetrameric model system with clearly defined properties and motile phases, we have constructed a tetrameric chimera by replacing the Eg5-motor domain and neck-linker by the homologous regions of D. melanogaster Kinesin 1 (DK4mer).

In surface-gliding assays, Dk4mer showed fast motility (553 +- 31 nm/s). Single GFP-tagged DK4mer motors moved processively along the MT at comparable speeds (499 +- 3 nm/s). We observe clearly distinguished directional and diffusional episodes and an overall run length of ~9 microns on average. We further performed relative sliding assays using DK4mer and polarity labeled MTs and show that DK4mer is capable of sliding MT apart simultaneously using both pairs of motor domains. The exact sliding speed was found to depend on ionic conditions. Direction of sliding appeared to alternate. This phenomenon could be due to additional surface-bound motors, to 1D diffusional motion or to an unlikely reversion of motor direction.