An Activity-Based Probe for Cathepsin K Imaging with Excellent Potency and Selectivity

  • J Med Chem. 2021 Sep 23;64(18):13793-13806. doi: 10.1021/acs.jmedchem.1c01178.
Carina Lemke  1 ,  Jakub Benýšek  2  3 ,  Dominik Brajtenbach  1 ,  Christian Breuer  1  4 ,  Adéla Jílková  2 ,  Martin Horn  2 ,  Michal Buša  2  5 ,  Lenka Ulrychová  2 ,  Annika Illies  1 ,  Katharina F Kubatzky  6 ,  Ulrike Bartz  4 ,  Michael Mareš  2 ,  Michael Gütschow  1
Affiliations
  • 1. Pharmaceutical Institute, Pharmaceutical & Medicinal Chemistry, University of Bonn, An der Immenburg 4, Bonn 53121, Germany.
  • 2. Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo n. 2, Prague 16610, Czech Republic.
  • 3. First Faculty of Medicine, Charles University, Kateřinská 32, Prague 12108, Czech Republic.
  • 4. Department of Natural Sciences, University of Applied Sciences Bonn-Rhein-Sieg, von-Liebig-Str. 20, Rheinbach 53359, Germany.
  • 5. Department of Biochemistry, Faculty of Science, Charles University, Hlavova 8, Prague 12800, Czech Republic.
  • 6. Department of Infectious Diseases, Medical Microbiology and Hygiene, Heidelberg University Hospital, Im Neuenheimer Feld 324, Heidelberg 69120, Germany.
PMID: 34473502 DOI: 10.1021/acs.jmedchem.1c01178
Abstract

The cysteine protease Cathepsin K is a target for the treatment of diseases associated with high bone turnover. Cathepsin K is mainly expressed in osteoclasts and responsible for the destruction of the proteinaceous components of the bone matrix. We designed various fluorescent activity-based probes (ABPs) and their precursors that bind to and inactivate Cathepsin K. ABP 25 exhibited extraordinary potency (kinac/Ki = 35,300 M-1s-1) and selectivity for human Cathepsin K. Crystal structures of Cathepsin K in complex with ABP 25 and its nonfluorescent precursor 21 were determined to characterize the binding mode of this new type of acrylamide-based Michael acceptor with the particular orientation of the dibenzylamine moiety to the primed subsite region. The cyanine-5 containing probe 25 allowed for sensitive detection of Cathepsin K, selective visualization in complex proteomes, and live cell imaging of a human osteosarcoma cell line, underlining its applicability in a pathophysiological environment.

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