Potent inhibitors of beta-tryptase and human leukocyte elastase based on the MCoTI-II scaffold.

MCoTI-II is a member of a class of microproteins known as cyclotides that possess a macrolactam-cystine knot scaffold imparting exceptional physiological stability and structural rigidity. Modification of residues in the active loop and engineered truncations have resulted in MCoTI-II analogues that possess potent activity against two therapeutically significant serine proteases: beta-tryptase and human leukocyte elastase. These results suggest that MCoTI-II is a versatile scaffold for the development of protease inhibitors against targets in inflammatory disease.