Normal and Impaired Charge Transport in Biological Systems

This talk will provide an overview of our experimental and theoretical work in biological physics. I will first review dielectric spectroscopy as a label-free method to probe changes in membrane potential of cells or mitochondria in suspension. Next, I will discuss some physical aspects of mutations – how the physics of DNA affects site-specific mutation rates, and how amino acid replacements affect certain biological motors.  Using ‘computational DNA hole spectroscopy,’ we have found that DNA mutates more readily at sites where electron holes tend to localize. This has implications for molecular evolution and for diseases affected by mutations.  I will then give a brief tutorial on physical aspects, including electron tunneling, of the electron transport chain (ETC) in mitochondria and bacteria. Finally, I will discuss our molecular dynamics studies of normal and mutation-impaired water channels in ATP synthase. Through molecular dynamics we have found that certain mitochondrial diseases, such as Leigh syndrome, are caused by a ‘short circuit’ between proton-conducting water channels, which impairs ATP production.

Prof. Miller received his Ph.D. at the University of Illinois in 1985, where he studied the dynamics of charge density waves under the direction of John Tucker and two-time Nobel Laureate John Bardeen. Prof. Miller was a faculty member in the Department of Physics and Astronomy at the University of North Carolina – Chapel Hill from 1986-1989, receiving the Alfred P. Sloan Research Fellowship in 1987. In 1989, he joined the University of Houston as a faculty member in the Department of Physics and the Texas Center for Superconductivity. Prof. Miller’s research has included superconductivity, charge density waves, physical properties of biological systems, and biological motors. https://tcsuh.com/people/prininv/miller_john/