EPR Interfaced To Rapid Mixing

Abstract

We describe the development of flow and stopped-flow EPR starting with large mixing devices designed for standard metallized EPR cavities and proceeding to micro mixing systems intimately attached to micro resonant structures. The characteristics of resonant structures dedicated to close attachment of liquid mixing systems with low dead volumes, short mixing times, and minimal microwave microphonic perturbation are outlined. The application of such systems to study of radical systems, either spin labelled, naturally occurring, or trapped, is reviewed, and recent experiments to probe rapid folding kinetics of site-directed spin labeled protein are summarized.