Structures of kobuviral and siciniviral polymerases reveal conserved mechanism of picornaviral polymerase activation

RNA-dependent RNA polymerase 3Dpol is a key enzyme for the replication of picornaviruses. The viral genome is translated into a single polyprotein that is subsequently proteolytically processed into matured products. The 3Dpol enzyme arises from a stable 3CD precursor that has high proteolytic activity but no polymerase activity. Upon cleavage of the precursor the newly established N-terminus of 3Dpol is liberated and inserts itself into a...