Structure and activity of human TMPRSS2 protease implicated in SARS-CoV-2 activation

Area of Science:

• Biochemistry
• Structural Biology
• Virology

Background:

• Transmembrane protease, serine 2 (TMPRSS2) is essential for SARS-CoV-2 entry by processing the viral Spike protein.
• Understanding TMPRSS2's function is critical for developing antiviral strategies against SARS-CoV-2.

Purpose of the Study:

• To produce enzymatically active TMPRSS2 for characterization.
• To determine the co-crystal structure of TMPRSS2 with nafamostat.
• To provide a structural basis for TMPRSS2 inhibition and guide selective drug development.

Main Methods:

• Recombinant production of enzymatically active TMPRSS2.
• X-ray crystallography to obtain a 1.95 Å co-crystal structure with nafamostat.
• Biochemical assays to assess protease activity and inhibitor potency (IC50 values).

Main Results:

• Enzymatically active TMPRSS2 was produced and characterized.
• The crystal structure revealed insights into nafamostat's non-specific inhibition and TMPRSS2's substrate binding pocket.
• TMPRSS2 cleaves the SARS-CoV-2 Spike protein at multiple sites, including S1/S2.
• Potency of clinical protease inhibitors was ranked (1.4 nM to 120 µM IC50).

Conclusions:

• The study provides structural insights into TMPRSS2 function and inhibition.
• This work lays the groundwork for developing selective TMPRSS2 inhibitors to combat SARS-CoV-2 infection.
• Understanding TMPRSS2-Spike protein interactions is key for antiviral drug discovery.