Poster Presentation The 48th Lorne Conference on Protein Structure and Function 2023

The baby steps of an artificial protein walker (#415)

Neil O Robertson 1 , Chu Wai Liew 1 , Roberta B Davies 1 , Nancy R Forde 2 , Birte Höcker 3 , Heiner Linke 4 , Paul M Curmi 1
  1. School of Physics and School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
  2. Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
  3. Department of Biochemistry, University of Bayreuth, Bayreuth, Germany
  4. NanoLund and Solid State Physics, University of Lund, Lund, Sweden

Nature has produced a large range of motor protein complexes that transform chemical energy into mechanical work. The remarkable efficiency of these motors makes life under far from equilibrium conditions possible. Despite their critical importance many aspects of their mechanisms are yet to be fully determined. These including the relative contributions of Brownian ratchet and power-stroke mechanisms, and how information is transduced across the motor. Natural motors are highly evolved and optimised machines, making reductionist studies of their mechanisms difficult. An alternate route is to design motors from scratch, where the mechanism of action can be rationally designed, modified and dissected. In the first step towards this overall goal, we have designed a three-legged artificial clocked protein walker, dubbed Tumbleweed. Tumbleweed is designed to walk on a DNA track using feet derived from ligand-dependent bacterial transcriptional repressor proteins. Alternating the flux of ligands will allow for the control of foot binding, enabling Tumbleweed to walk along a track. We have purified the designed components and assembled them into a single functional unit using native protein ligation techniques. We are characterising the binding of Tumbleweed to track using a range of biophysical techniques, including surface plasmon resonance (SPR), mass photometry and Förster resonance energy transfer (FRET) spectroscopy. These techniques will allow for the initial investigation of Tumbleweed’s stepping activity. Our studies of Tumbleweed will provide the basis for designing, producing and characterising more complex artificial autonomous protein motors, which in turn will help illuminate the fundamental mechanisms of natural protein motors.