Reversible targeting of noncatalytic cysteines with chemically tuned electrophiles

TY - JOUR

T1 - Reversible targeting of noncatalytic cysteines with chemically tuned electrophiles

AU - Serafimova, Iana M

AU - Pufall, Miles A

AU - Krishnan, Shyam

AU - Duda, Katarzyna

AU - Cohen, Michael S

AU - Maglathlin, Rebecca L

AU - McFarland, Jesse M

AU - Miller, Rand M

AU - Frödin, Morten

AU - Taunton, Jack

PY - 2012/5

Y1 - 2012/5

N2 - Targeting noncatalytic cysteine residues with irreversible acrylamide-based inhibitors is a powerful approach for enhancing pharmacological potency and selectivity. Nevertheless, concerns about off-target modification motivate the development of reversible cysteine-targeting strategies. Here we show that electron-deficient olefins, including acrylamides, can be tuned to react with cysteine thiols in a rapidly reversible manner. Installation of a nitrile group increased the olefins' intrinsic reactivity, but, paradoxically, eliminated the formation of irreversible adducts. Incorporation of these electrophiles into a noncovalent kinase-recognition scaffold produced slowly dissociating, covalent inhibitors of the p90 ribosomal protein S6 kinase RSK2. A cocrystal structure revealed specific noncovalent interactions that stabilize the complex by positioning the electrophilic carbon near the targeted cysteine. Disruption of these interactions by protein unfolding or proteolysis promoted instantaneous cleavage of the covalent bond. Our results establish a chemistry-based framework for engineering sustained covalent inhibition without accumulating permanently modified proteins and peptides.

AB - Targeting noncatalytic cysteine residues with irreversible acrylamide-based inhibitors is a powerful approach for enhancing pharmacological potency and selectivity. Nevertheless, concerns about off-target modification motivate the development of reversible cysteine-targeting strategies. Here we show that electron-deficient olefins, including acrylamides, can be tuned to react with cysteine thiols in a rapidly reversible manner. Installation of a nitrile group increased the olefins' intrinsic reactivity, but, paradoxically, eliminated the formation of irreversible adducts. Incorporation of these electrophiles into a noncovalent kinase-recognition scaffold produced slowly dissociating, covalent inhibitors of the p90 ribosomal protein S6 kinase RSK2. A cocrystal structure revealed specific noncovalent interactions that stabilize the complex by positioning the electrophilic carbon near the targeted cysteine. Disruption of these interactions by protein unfolding or proteolysis promoted instantaneous cleavage of the covalent bond. Our results establish a chemistry-based framework for engineering sustained covalent inhibition without accumulating permanently modified proteins and peptides.

KW - Acrylamides

KW - Alkenes

KW - Cysteine

KW - Nitriles

KW - Protein Unfolding

KW - Proteolysis

KW - Ribosomal Protein S6 Kinases, 90-kDa

KW - Sulfhydryl Compounds

U2 - 10.1038/nchembio.925

DO - 10.1038/nchembio.925

M3 - Journal article

C2 - 22466421

SN - 1552-4450

VL - 8

SP - 471

EP - 476

JO - Nature Chemical Biology

JF - Nature Chemical Biology

IS - 5

ER -