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Engineering Approaches to Biomolecular Motors: From in vitro to in vivo Poster Abstracts
52
27-POS
Board 27
Forestep-Backstep Ratio Determines Stall Force for both Fast and Slow Kinesin-1
Algirdas Toleikis
, Nicholas J. Carter, Robert A. Cross.
University of Warwick, Coventry, United Kingdom.
Kinesin-1 is a motor protein responsible for molecular transport inside cells. It consumes ATP as
an energy source required to do work and transports cargos while walking on microtubule tracks.
Kinesin-1 is a processive motor and can walk ~100 steps before falling off. It walks in ~8 nm
steps in a hand-over-hand fashion and stalls at ~7 pN backwards (hindering) force. At this stall
force, steps are infrequent so backstepping and forward stepping are equally probable. In this
work, we are using optical trapping to apply directional force on single kinesins in vitro to study
the mechanism of stepping. Particularly, we are focusing on the directionality of stepping,
counting forward vs backward steps at a particular force, and interrogating the mechanism
underlying the switch of direction. We are comparing kinesin-1 isoforms from Drosophilla and
Neurospora to better understand how nature has engineered changes in amino acid sequence that
influence the stepping behaviour. We present preliminary data which we hope in the future might
help us understand the mechanistic determinants of stepping directionality.