Defining the druggable cysteinome

ORGN 242

Jack Taunton, taunton@cmp.ucsf.edu, University of California, San Francisco, San Francisco, CA 94158
Electrophilic enzyme inhibitors that form a covalent bond with a catalytic, active-site nucleophile have a long history in 'rational drug design'. Less well known is that two blockbuster drugs discovered by chance (omeprazole and clopidogrel) form covalent bonds with cysteine thiols that apparently do not have any catalytic function. I will discuss our efforts to systematically define and exploit this "druggable cysteinome", beginning with the protein kinase superfamily. We have designed several kinase inhibitors that owe their potency and, more importantly, their selectivity, to covalent bond formation with non-catalytic cysteines that are poorly conserved among the 500 human kinases. We have recently developed reversible covalent inhibitors and are working to extend this approach to targets beyond the kinase superfamily.