Picornaviruses

The picornavirus family contains several major human and animal pathogens. Vaccines against some of these pathogens are available. However, the availability of potent antiviral compounds would be an appreciable advantage in fighting these pathogens. Inside their non-enveloped capsid, picornaviruses possess a positive sense RNA genome with a single open reading frame. Upon release into the cytoplasm, the genome is translated into a single polyprotein that is processed by virally encoded proteinases. These proteinases represent excellent targets for the development of anti-virals for two reasons. First, efficient polyprotein processing is essential for successful viral replication. Second, the picornaviral proteinases show notable differences to cellular proteinases. To aid in the development of anti-virals, detailed knowledge of the mechanisms, substrate specificities and structures of these proteinases is needed. This chapter reviews recent progress, discusses selected substances with antiviral activity against picornavirus proteinases and outlines several new avenues for the design of novel anti-virals.