Abstract
The leader (L) peptide is located in the amino-terminal part of the polyprotein of members of the Cardiovirus (which includes Theiler's murine encephalomyelitis virus) and Aphthovirus genera of picornaviruses. Although the function of L is unknown, strain DA of Theiler's murine encephalomyelitis virus with a mutation of L produces a cell-specific restricted infection. We now report that the DA L peptide is a metalloprotein and that zinc binds to a Cys-His motif that is conserved among cardioviruses.