Condensed Matter Physics Seminar

Prof. Bob Eisenberg, Dept of Molecular Biophysics & Physiology, Rush University, Chicago, IL. USA

Friday 30 October 2015, 1500-1600
Furness Lecture Theatre 2

The English Approach to Calcium Channels: the Physiology and Physics of Devices - Calcium channels control an enormous range of biological function from contraction of the heart to (probably) short term memory and learning. Calcium signals are as important in biological systems as a gas (petrol) pedal is in controlling the speed of a car. Ion channels can be studied in the tradition of English physiology, developed by (the first Lord) Adrian and Hodgkin, more than anyone else from ideas known to Aristotle, now extended to atomic detail, incorporating modern ideas of reverse engineering and evolutionary biology. Channels are treated as devices with definite relations between inputs and outputs, using the physics of electric current flow and diffusion to drive movements of ions that produce electrical signals, changes in concentration and thereby control biochemical systems. Physics and math(s) are central because flows are always present: classical chemistry and thermodynamics assumes zero flows and neglects electrical current. Here I show how the English approach can account for all the properties of the open RyR ryanodine receptor that controls intracellular movements of calcium. Dirk Gillespie actually predicted subtle results before meaurements were made). All the measured properties of the open calcium channel of the heart; and many properties of the open sodium channel discovered by Hodgkin are explained. The structure of these channels has great importance, and the details of atomic movement are also important in special cases, but the main themes of function are invisible in structures, not present in atomic simulations (e.g., trace electric current and trace concentrations of calcium and messengers), and absent from chemical theories that assume equilibrium.