Journal Article

Potent, multi-target serine protease inhibition achieved by a simplified β-sheet motif

Leahy, Darren, Brattsand, Maria, Hartfield, Perry J., Buckle, Ashley M., Swedberg, Joakim E., Harris, Jonathan M., Chen, Xingchen, Van Haeften, Jessica, de Veer, Simon J., Hoke, David E., Riley, Blake T.

2019

Overview

Engagement of an extended β-sheet is a common substrate/inhibitor interaction at the active site of serine proteases and is an important feature of Laskowski mechanism inhibitors that present a substrate-like loop to a target protease. This loop is cleaved but subsequently relegated forming a stable inhibitor/protease complex. Laskowski inhibitors are ubiquitous in nature and are used extensively in serine protease inhibitor design. However, most studies concentrate on introducing new sidechain interactions rather than the direct contributions of the substrate-like β-sheet to enzyme inhibition. Here we report the crystal structure of an simplified β-sheet inhibitory motif within the Sunflower Trypsin Inhibitor (SFTI) in complex with trypsin. We show that the intramolecular hydrogen bond network of this SFTI variant (SFTI-TCTR) engages the inhibitor sidechains that would normally interact with a target protease, giving mainchain interactions a more prominent role in complex formation. Despite having reduced sidechain interactions, this SFTI variant is remarkably potent and inhibits a diverse range of serine proteases. Crystal structural analysis and molecular modelling of SFTI-TCTR complexes again indicates an interface dominated by β-sheet interactions, highlighting the importance of this motif and the adaptability of SFTI as a scaffold for inhibitor design.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adaptability / Amino Acid Motifs / Animals / Biochemistry / Biology and Life Sciences / Cattle / Complex formation / Crystal structure / Crystallography, X-Ray / Design / Enzymes / Helianthus - chemistry / Hydrogen / Hydrogen Bonding / Hydrogen bonds / Models, Molecular / Molecular biology / Molecular Dynamics Simulation / Molecular modelling / Peptides, Cyclic - chemistry / Peptides, Cyclic - pharmacology / Physical Sciences / Plant Proteins - chemistry / Plant Proteins - pharmacology / Protease / Protease inhibitors / Protein Conformation, beta-Strand / Protein Interaction Domains and Motifs / Proteinase inhibitors / Proteins / Serine / Serine proteinase / Serine Proteinase Inhibitors - chemistry / Serine Proteinase Inhibitors - pharmacology / Signal transduction / Static Electricity / Structural analysis / Substrate inhibition / Substrates / Trypsin / Trypsin - chemistry / Trypsin inhibitors / Trypsin Inhibitors - chemistry / Trypsin Inhibitors - pharmacology