PMID: 12563278 , Related PDB ids: 1NME, 1NMQ, 1NMS
Erlanson DA, Lam JW, Wiesmann C, Luong TN, Simmons RL, DeLano WL, Choong IC, Burdett MT, Flanagan WM, Lee D, Gordon EM, O'Brien T
In situ assembly of enzyme inhibitors using extended tethering.
Nat Biotechnol. 2003 Mar;21(3):308-14. Epub 2003 Feb 3.
Cysteine aspartyl protease-3 (caspase-3) is a mediator of apoptosis and a therapeutic target for a wide range of diseases. Using a dynamic combinatorial technology, 'extended tethering', we identified unique nonpeptidic inhibitors for this enzyme. Extended tethering allowed the identification of ligands that bind to discrete regions of caspase-3 and also helped direct the assembly of these ligands into small-molecule inhibitors. We first designed a small-molecule 'extender' that irreversibly alkylates the cysteine residue of caspase-3 and also contains a thiol group. The modified protein was then screened against a library of disulfide-containing small-molecule fragments. Mass-spectrometry was used to identify ligands that bind noncovalently to the protein and that also form a disulfide linkage with the extender. Linking the selected fragments with binding elements from the extenders generates reversible, tight-binding molecules that are druglike and distinct from known inhibitors. One molecule derived from this approach inhibited apoptosis in cells.