paper

Energetic costs, precision, and efficiency of a biological motor in cargo transport

arXiv:1710.03499 · doi:10.1021/acs.jpclett.7b03197

Abstract

Molecular motors play pivotal roles in organizing the interior of cells. A motor efficient in cargo transport would move along cytoskeletal filaments with a high speed and a minimal error in transport distance (or time) while consuming a minimal amount of energy. The travel distance of the motor and its variance are, however, physically constrained by the free energy being consumed. A recently formulated \emph{thermodynamic uncertainty relation} offers a theoretical framework for the energy-accuracy trade-off relation ubiquitous in biological processes. According to the relation, a measure , the product between the heat dissipated from a motor and the squared relative error in the displacement, has a minimal theoretical bound (), which is approached when the time trajectory of the motor is maximally regular for a given amount of free energy input. Here, we use to quantify the transport efficiency of biological motors. Analyses on the motility data from several types of molecular motors reveal that is a complex function of ATP concentration and load (). For kinesin-1, approaches the theoretical bound at pN and over a broad range of ATP concentration (1 M - 10 mM), and is locally minimized at [ATP] 200 M. In stark contrast, this local minimum vanishes for a mutant that has a longer neck-linker, and the value of is significantly greater, which underscores the importance of molecular structure. Transport efficiencies of the biological motors studied here are semi-optimized under the cellular condition ([ATP] mM, pN). Our study indicates that among many possible directions of optimization, cytoskeletal motors are designed to operate at a high speed with a minimal error while leveraging their energy resources.

6 figures, 15 supplementary figures

References in corpus (6)

Cited by in corpus (57)