Using high resolution cryo electron microscopy (Cryo EM) we will investigate the mechanisms used by coxsackievirus B3 (CVB3) to enter host cells by engaging the coxsackievirus and adenovirus receptor (CAR). CVB3 is a human pathogen that causes myocarditis, pancreatitis, and has recently been linked to the onset of juvenile diabetes mellitus. Our proposed studies of CVB3 entry are a continuation of a productive previous granting period. Part of the previous work done was in collaboration with Dr. Jeffery Bergelson, Division of Infectious Diseases at Children's Hospital at Philadelphia, who has since retired. The proposed projects to continue studies of enterovirus entry include a collaboration with Konstantin Chumakov, FDA. Chumakov will work with us to explore one of the most promising results from the previous funding period, which was the discovery that a region in the CAR footprint onto the CVB3 capsid is conserved among three other viruses and their receptors, thus crossing four species using three different host proteins for entry. Further examination showed 1) the region is highly conserved among all human enteroviruses, including all three strains of poliovirus. 2) there are in total four different highly conserved regions. Previous work and our preliminary results link these conserved sites to functions linked to entry. Our structure/function studies will include testing each region for function and as targets for antivirals that are desperately needed. We will use both traditional icosahedrally averaged approaches along with asymmetric reconstruction approaches, some of which have been recently developed by us.