In Professor Shin’s laboratory a new spin labeling EPR approach is used to study the structure and function of biologically important membrane proteins. The strategy is to site-specifically place a nitroxide spin label in the protein by replacing a native residue with cysteine, which provides a unique labeling sites. Current developments of EPR technology make it possible to obtain information on secondary and tertiary structures as well as membrane topology using spin labeled mutants. Unlike crystallographic methods, the EPR approach does not require crystallization of proteins. Thus, the EPR methods are widely applicable to studies of many important membrane proteins. Furthermore, the mechanistic aspects of the function of the membrane proteins are studied using the time-resolved EPR techniques. Specific areas of current interest include: The viral envelope proteins: influenza HA and HIV gp160 and Transmembrane signal transduction.