Structure of a proteolytically resistant analogue of (NLys)⁵SFTI-1 in complex with trypsin: evidence for the direct participation of the Ser214 carbonyl group in serine protease-mediated proteolysis

The structure of a peptide–peptoid analogue inhibitor was determined by X-ray crystallography. It is the first structure to reveal the structural basis of the complete proteolytic resistance towards serine proteases by inhibitors containing a peptoid residue at the P1 position.