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BP: Fachverband Biologische Physik

BP 15: Single-Molecule Biophysics I

BP 15.7: Vortrag

Dienstag, 15. März 2011, 12:15–12:30, ZEU 250

Weak kinesin-8 steps and slips on Microtubules — •Anita Jannasch¹, Marko Storch², Jonathon Howard², and Erik Schäffer¹ — ¹Nanomechanics Group, Biotechnology Center, TU Dresden, Tatzberg 47-51, 01307 Dresden, Germany — ²Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany

The budding yeast kinesin-8 motor, Kip3p, is a very processive plus-end directed motor protein. In addition, Kip3p is a microtubule length-dependent depolymerase. Here, we studied the operation of Kip3p under load using optical tweezers as a force and position sensitive tool. We expressed and purified the recombinant Kip3p-GFP fusion protein and attached it to a microsphere surface via a polyethylenglycol linker preserving its full functionality. Our studies show that single Kip3p can carry cargo with a stall force of 1.2 pN while moving with 8 nm steps along the microtubule. The velocity of the motor strongly depended on the load force. Furthermore, the motor started to slip under load. Compared to conventional kinesin, Kip3p is a slow and weak motor, which might be a trade-off for its high processivity.