title: An Irreversible Inhibitor of HSP72 that Unexpectedly Targets Lysine-56.
abstract: The stress-inducible molecular chaperone, HSP72, is an important therapeutic target in oncology, but inhibiting this protein with small molecules has proven particularly challenging. Validating HSP72 inhibitors in cells is difficult owing to competition with the high affinity and abundance of its endogenous nucleotide substrates. We hypothesized this could be overcome using a cysteine-targeted irreversible inhibitor. Using rational design, we adapted a validated 8-N-benzyladenosine ligand for covalent bond formation and confirmed targeted irreversible inhibition. However, no cysteine in the protein was modified; instead, we demonstrate that lysine-56 is the key nucleophilic residue. Targeting this lysine could lead to a new design paradigm for HSP72 chemical probes and drugs.
authors.affiliation: Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, London, SW7 3RP, UK.
authors.forename: Jonathan
authors.identifier: 0000-0002-8219-8369
authors.initials: J
authors.lastname: Pettinger
authors.affiliation: Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, London, SW7 3RP, UK.|Division of Structural Biology, The Institute of Cancer Research, London, SW7 3RP, UK.
authors.forename: Yann-Vaï
authors.identifier: 0000-0002-6850-9706
authors.initials: YV
authors.lastname: Le Bihan
authors.affiliation: Proteomics Core Facility, The Institute of Cancer Research, London, SW7 3RP, UK.
authors.forename: Marcella
authors.initials: M
authors.lastname: Widya
authors.affiliation: Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, London, SW7 3RP, UK.|Division of Structural Biology, The Institute of Cancer Research, London, SW7 3RP, UK.
authors.forename: Rob L M
authors.initials: RL
authors.lastname: van Montfort
authors.affiliation: Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, London, SW7 3RP, UK.
authors.forename: Keith
authors.identifier: 0000-0002-9440-4094
authors.initials: K
authors.lastname: Jones
authors.affiliation: Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, London, SW7 3RP, UK.
authors.forename: Matthew D
authors.identifier: 0000-0003-1121-6985
authors.initials: MD
authors.lastname: Cheeseman
keywords: fluorescence polarization; irreversible inhibitors; mass spectrometry; medicinal chemistry; structural biology