Design principles of molecular machines: efficient control and functional coupling

Synopsis

Biomolecular machines are central actors in essentially all core 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, and how to allocate nonequilibrium driving forces among the steps of a machine cycle to maximize its throughput. These theoretical results find confirmation in experiments and provide nontrivial yet intuitive implications for the design principles of molecular-scale energy transduction.