Mutational Analysis of the Putative Substrate-binding Site of 3C Proteinase of Coxsackievirus B3

Abstract

Single amino acid substitutions were introduced into the putative substrate-binding site of 3C proteinase (3C^pro) of coxsackievirus B3, a member of the picornavirus family. Mutations at either Thr142, His161, Gly164, Gly169, or Ala172 severely impaired or abolished the proteolytic activity except that a conservative Thr142to Ser mutant had detectable activity. These results, which have shown the participation of the 5 residues in 3C^pro activity, are consistent with the earlier predictions that these residues might be involved in substrate binding.