In situ assembly of enzyme inhibitors using extended tethering.
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.
Erlanson
Daniel A
DA
Sunesis Pharmaceuticals, Inc., 341 Oyster Point Boulevard, South San Francisco, CA 94080, USA. erlanson@sunesis.com
Lam
Joni W
JW
Wiesmann
Christian
C
Luong
Tinh N
TN
Simmons
Robert L
RL
DeLano
Warren L
WL
Choong
Ingrid C
IC
Burdett
Matthew T
MT
Flanagan
W Michael
WM
Lee
Dennis
D
Gordon
Eric M
EM
O'Brien
Tom
T
D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000737:chemistry* / Q000378:metabolism; D020650:Combinatorial Chemistry Techniques / Q000379:methods*; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000145:classification / Q000494:pharmacology*; D006801:Humans; D019169:Jurkat Cells / Q000187:drug effects* / Q000378:metabolism; D013058:Mass Spectrometry / Q000379:methods; D008958:Models, Molecular; D019151:Peptide Library
D061945:Caspase Inhibitors; D004791:Enzyme Inhibitors; D019151:Peptide Library; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases