[Tobacco etch virus proteinase: crystal structure of the active enzyme and its inactive mutant].

Tobacco Etch Virus Protease (TEV protease) is widely used as a tool for separation of recombinant target proteins from their fusion partners. The crystal structures of two mutants of TEV protease, active autolysis-resistant mutant TEV-S219D in complex with the proteolysis product, and inactive mutant TEV-C151A in complex with a substrate, have been determined at 1.8 and 2.2 A resolution, respectively. The active sites of both mutants, including their oxyanion holes, have identical structures. The C-terminal residues 217-221 of the enzyme are involved in formation of the binding pockets S3-S6. This indicates that the autolysis of the peptide bond Met218-Ser219 exerts a strong effect on the fine-tuning of the substrate in the enzyme active site, which results in considerable decrease in the enzymatic activity.