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Title: Small molecule inhibitors of mesotrypsin from a structure-based docking screen

PRSS3/mesotrypsin is an atypical isoform of trypsin, the upregulation of which has been implicated in promoting tumor progression. To date there are no mesotrypsin-selective pharmacological inhibitors which could serve as tools for deciphering the pathological role of this enzyme, and could potentially form the basis for novel therapeutic strategies targeting mesotrypsin. A virtual screen of the Natural Product Database (NPD) and Food and Drug Administration (FDA) approved Drug Database was conducted by high-throughput molecular docking utilizing crystal structures of mesotrypsin. Twelve high-scoring compounds were selected for testing based on lowest free energy docking scores, interaction with key mesotrypsin active site residues, and commercial availability. Diminazene (C1D22956468), along with two similar compounds presenting the bis-benzamidine substructure, was validated as a competitive inhibitor of mesotrypsin and other human trypsin isoforms. Diminazene is the most potent small molecule inhibitor of mesotrypsin reported to date with an inhibitory constant (K i) of 3.6±0.3 pM. Diminazene was subsequently co-crystalized with mesotrypsin and the crystal structure was solved and refined to 1.25 Å resolution. This high resolution crystal structure can now offer a foundation for structure-guided efforts to develop novel and potentially more selective mesotrypsin inhibitors based on similar molecular substructures.
 [1] ;  [2] ;  [3] ;  [4] ;  [2] ;  [2] ; ORCiD logo [1]
  1. Mayo Clinic Comprehensive Cancer Center, Jacksonville, FL (United States). Department of Cancer Biology
  2. University of Minnesota, Austin, MN (United States). The Hormel Institute
  3. Brookhaven National Lab. (BNL), Upton, NY (United States). Photon Sciences Directorate
  4. Mayo Clinic College of Medicine, Jacksonville, FL (United States). Department of Neuroscience
Publication Date:
Report Number(s):
Journal ID: ISSN 1932-6203
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Additional Journal Information:
Journal Volume: 12; Journal Issue: 5; Journal ID: ISSN 1932-6203
Public Library of Science
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); National Institutes of Health (NIH)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; mesotrypsin; trypsin; serine protease; protease inhibitor; drug discovery; structure-based docking; in-silico screening; virtual screening; crystal structure; x-ray crystallography
OSTI Identifier: