The role of kinetic asymmetry and power strokes in an information ratchet

Lorna Binks, Stefan Borsley, Todd R. Gingrich, David A. Leigh*, Emanuele Penocchio, Benjamin M.W. Roberts

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Biomolecular machines are driven by information ratchet mechanisms, where kinetic asymmetry in the machine's chemomechanical cycle of fuel-to-waste catalysis induces net directional dynamics. A large-scale energetically downhill conformational change, termed a “power stroke,” has often been erroneously implicated as a mechanistic driving feature in such machines. We investigated the roles of kinetic asymmetry and power strokes in a series of rotaxane-based information ratchets and found that kinetic asymmetry alone determines ratchet directionality such that all ratchets use the same amount of fuel to reach the same normalized steady state. However, power strokes can nonetheless influence ratchet performance, such as how fast the steady state is reached. Moreover, nonequilibrium thermodynamic analysis revealed that power strokes alter the amount and form (information [Shannon entropy] versus intercomponent binding energy) of the free energy stored by ratchets. These findings have implications for both the understanding of biological ratchets and the design principles for artificial nonequilibrium (supra)molecular machines.

Original languageEnglish (US)
Pages (from-to)2902-2917
Number of pages16
JournalChem
Volume9
Issue number10
DOIs
StatePublished - Oct 12 2023

Funding

We acknowledge support from the European Research Council (ERC Advanced Grant 786630 ), the Engineering and Physical Sciences Research Council (EPSRC) (grant EP/P027067/1 ), the Gordon and Betty Moore Foundation (grant GBMF10790 to T.R.G.), and the University of Manchester and EPSRC for PhD studentships to L.B. and B.M.W.R. D.A.L. is a Royal Society Research Professor.

Keywords

  • Brownian ratchets
  • SDG7: Affordable and clean energy
  • SDG9: Industry, innovation, and infrastructure
  • information thermodynamics
  • kinetic analysis
  • molecular machines
  • nonequilibrium chemistry
  • rotaxanes

ASJC Scopus subject areas

  • General Chemistry
  • Biochemistry
  • Environmental Chemistry
  • General Chemical Engineering
  • Biochemistry, medical
  • Materials Chemistry

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