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

Area of Science:

• Biochemistry
• Enzymology
• Pharmacology

Background:

• Mesotrypsin (PRSS3) is an atypical trypsin isoform linked to tumor progression.
• Selective pharmacological inhibitors for mesotrypsin are lacking, hindering research and therapeutic development.

Purpose of the Study:

• To identify selective small molecule inhibitors of mesotrypsin.
• To provide tools for deciphering the pathological role of mesotrypsin.
• To lay the groundwork for novel therapeutic strategies targeting mesotrypsin.

Main Methods:

• Virtual screening using high-throughput molecular docking against mesotrypsin crystal structures.
• Selection of 12 high-scoring compounds for experimental validation.
• Co-crystallization of the identified inhibitor with mesotrypsin and high-resolution structure determination.

Main Results:

• Diminazene was identified as a potent competitive inhibitor of mesotrypsin (Ki = 3.6±0.3 μM).
• Diminazene also inhibits other human trypsin isoforms.
• A high-resolution (1.25 Å) crystal structure of diminazene-bound mesotrypsin was obtained.

Conclusions:

• Diminazene is the most potent mesotrypsin inhibitor reported to date.
• The crystal structure provides a foundation for structure-guided design of novel, selective mesotrypsin inhibitors.
• This work facilitates further research into mesotrypsin's role in disease and potential therapeutic interventions.