Design principles of molecular machines: efficient control and functional coupling

1 March 2019

David Sivak
Department of Physics
Simon Fraser University, Canada


Biomolecular machines are central actors in a myriad of major cell biological process. Their successful function requires effective energy conversion and handoff between diverse mechanical components, and symmetry-breaking to achieve directed transport. It seems plausible that evolution has sculpted these machines to effectively transduce free energy in their natural contexts, where stochastic fluctuations are large, nonequilibrium driving forces are strong, and biological imperatives require rapid turnover. But what are the physical limits on such nonequilibrium effectiveness, and what machine designs actually achieve these limits? In this talk, I discuss how to rapidly and efficiently drive such noisy systems from one state to another, how to allocate nonequilibrium driving forces among the steps of a machine cycle to maximize its throughput, and how strong coupling to the environment radically alters the tradeoffs these machines face. These theoretical results find confirmation in experiments and provide nontrivial yet intuitive implications for the design principles of molecular-scale energy transduction.

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