Efficient energy and information transduction in microscopic nonequilibrium systems

点击翻译按钮获取中文摘要

One of the most fundamental physical principles states that disorder always increases, yet living things must maintain order to function effectively. Via constant input of high-energy molecules and output of low-energy waste, they stay far from the more disordered state known as equilibrium. ******Unfortunately, physical theories of biological systems have generally assumed that the system is at equilibrium, mainly because the mathematics is simpler. But in recent years, significant advances in nonequilibrium theory point to the possibility of general principles that characterize living systems. Such theoretical developments have improved our understanding of how a single molecule (e.g., a protein or DNA molecule) resists stretching. The theories are, however, still too simple to adequately describe more complex biological systems and more subtle interventions. ******I hypothesize that efficient energy usage and information processing provides a selective advantage, thereby leading to an evolutionary force to improve these properties in biological systems. Thus, through theoretical analysis of optimal energetic and information-theoretic efficiency in microscopic model systems far from equilibrium, I will formulate strong and testable predictions about the dynamical properties of biomolecular machines sculpted by evolution. ******To make this applicable to a wider range of biological phenomena, I will develop nonequilibrium theory that focuses on: the random jostling that microscopic objects constantly encounter from neighboring molecules; the fact that biological components are inextricably connected to many other things and must act appropriately in these interactions in order to function well; and the transduction of information and energy through changing numbers of proteins in a cell. This work will involve fundamental theory, exploration of simple models, more detailed numerical calculations on complex systems, and close collaboration with experimentalists to test the validity and utility of our theories. ******My research program, involving the training of several scientists in my group, will uncover rigorous physical constraints on how biological systems can behave given the operational imperatives they face, such as when biological systems are driven far from equilibrium. These experiments will help elucidate basic design principles for energetically-efficient biological function. Ultimately, we may obtain a better understanding of the goals of evolution and its physical constraints. This work will also aid the design of new molecular-sized devices to achieve technological goals such as sustainable energy harvesting, efficient information storage and manipulation, or targeted delivery of therapeutic agents.