Development of a microstructured magnetic system to measure force-velocity-characteristics generated by collectives of kinesin molecules (Entwicklung eines mikrostrukturierten magnetischen Meßsystems zur Bestimmung von Kraft-Geschwindigkeits-Charakteristika bei Kinesin-Molekülkollektiven)

• Applicant: Professor Dr. Eberhard Unger
• Subject Area: Biophysics
• Term: from 1999 to 2002
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5176402

Molecular systems of the kinesin-tubulin type essentially contribute to intracellular dynamic processes, e.g., in chromosome movement or vesicle transport. By hydrolysing ATP force is generated and transformed into directed motions also in vitro. It is well-known that single kinesin molecules produce forces near 5 pN during 8 nm step movements along microtubules. Relations between the collective force generation of molecular kinesin populations, the resulting speed of loads driven by such collectives, and the maximum force exerted, however, have not been determined. The aim of this project is to record force-velocity characteristics versus the kinesin molecule number of driving collectives. In preliminary investigations we have shown that the speed of gliding microtubules inversely correlates to the kinesin concentration. It should be proven whether this is due to a slowing down of the specific force generation per molecule (resulting from a partial cancellation of the single molecular unit force) or the speed of the mechano-chemical cycle, both at a given set of cofactors. The speed to force relations and the maximum / stall forces will be investigated using a new methodical approach. Force measurements will be performed by the interaction of a known external magnetic field with small magnetic particles (beads) bound to microtubular loads.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1068: Molekulare Motoren