Abst:
The input-output relations of a molecular machine summarize its biological functional characteristics. Therefore, answering many fundamental questions on molecular machines ultimately reduce to understanding their input-output relations. Many chemical reactions, particularly reactions catalyzed by enzymes, follow one of the few “universal” relations between input concentrations and output concentration of the molecular species involved in the reaction. We begin with a graph theoretic analysis of the input-output relation of a single enzyme. Input-output response of a graph can be characterized by the steady-state concentrations of the vertices. This analysis sets the stage for understanding, at the next level of complexity, the input-output relation of a molecular machine, that is a macromolecular complex, and then at an even broader context of a group of interacting machines. I'll present an overview of our recent results on these input-output relations at multiple scales.