Figure 1.

Strategy for designing KLK4 inhibitors based on MCoTI-II. Ribbon diagram of SFTI-FCQR (left, PDB ID 4K1E) and MCoTI-II (right, PDB ID 4GUX) with disulfide bonds shown in ball and stick representation. The modified residues in SFTI-FCQR are shown in stick model (P4 Phe, P2 Gln and P1 Arg) with carbon atoms in cyan. The P4–P1 segment of MCoTI-II (cyan) has the same structure as SFTI-FCQR, allowing substitution of the FCQR sequence into MCoTI-II to generate the KLK4 inhibitor MC-FCQR. The sequence of each inhibitor is shown in single letter amino acid code (colored to match the ribbon diagram).