IMPLICATIONS FOR VIRAL UNCOATING FROM THE STRUCTURE OF BOVINE ENTEROVIRUS

We have determined the crystal structure of a bovine enterovirus, reve aling that the topologies of the major capsid proteins and the overall architecture of the virion are similar to those of related picornavir uses. The external loops joining beta-strands are truncated and the ca nyon region is partially filled by an extension of the VPS G-H loop gi ving the viral capsid a relatively smooth appearance. These changes ma y have implications for cell attachment. In spite of these differences the virus maintains a hydrophobic pocket within VP1, occupied by a sp ecific 'pocket factor' which appears to be myristic acid. These observ ations support the proposal that a kinetic equilibrium exists between occupied and unoccupied pocket states, with occupation inhibiting unco ating.