The structures of picornaviral proteinases

Picornaviruses are a family of positive-strand RNA viruses the members of w hich include poliovirus, hepatitis A virus, rhinovirus, foot-and-mouth dise ase virus and encephalomyocarditis virus. The genetic information contained in the single-stranded, positive sense RNA genome is expressed as a single protein of around 2000 amino acids. This primary product of protein synthe sis, designated the polyprotein, is subsequently cleaved into the mature vi ral proteins by proteinases present within it. The properties of the three defined proteolytic activities present in the picornaviruses are reviewed a nd the three-dimensional structures of the hepatitis A 3C proteinase and th e leader proteinase of foot-and-mouth disease virus as well as a model of t he structure of the HRV2 2A proteinase are compared with those of chymotryp sin, papain and streptomyces griseus A proteinase, respectively. (C) 1999 E lsevier Science B.V. All rights reserved.