USP7-Specific Inhibitors Target and Modify the Enzyme's Active Site via Distinct Chemical Mechanisms

Cell Chem Biol. 2017 Dec 21;24(12):1501-1512.e5. doi: 10.1016/j.chembiol.2017.09.004. Epub 2017 Oct 19.


USP7 is a deubiquitinating enzyme that plays a pivotal role in multiple oncogenic pathways and therefore is a desirable target for new anti-cancer therapies. However, the lack of structural information about the USP7-inhibitor interactions has been a critical gap in the development of potent inhibitors. USP7 is unique among USPs in that its active site is catalytically incompetent, and is postulated to rearrange into a productive conformation only upon binding to ubiquitin. Surprisingly, we found that ubiquitin alone does not induce an active conformation in solution. Using a combination of nuclear magnetic resonance, mass spectrometry, computational modeling, and cell-based assays, we found that DUB inhibitors P22077 and P50429 covalently modify the catalytic cysteine of USP7 and induce a conformational switch in the enzyme associated with active site rearrangement. This work represents the first experimental insights into USP7 activation and inhibition and provides a structural basis for rational development of potent anti-cancer therapeutics.

Keywords: DUB inhibition; DUBs; NMR; USP7; covalent inhibitors; cysteine peptidase; mass spectrometry; ubiquitin binding.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Catalytic Domain
  • Humans
  • Models, Molecular
  • Molecular Structure
  • Protease Inhibitors / chemistry
  • Protease Inhibitors / pharmacology*
  • Structure-Activity Relationship
  • Substrate Specificity
  • Thiophenes / chemistry
  • Thiophenes / pharmacology*
  • Ubiquitin / metabolism
  • Ubiquitin-Specific Peptidase 7 / antagonists & inhibitors*
  • Ubiquitin-Specific Peptidase 7 / metabolism


  • 1-(5-((2,4-difluorophenyl)thio)-4-nitrothiophen-2-yl)ethanone
  • Protease Inhibitors
  • Thiophenes
  • Ubiquitin
  • Ubiquitin-Specific Peptidase 7