Structural basis of TMPRSS11D specificity and autocleavage activation.

Area of Science:

• Biochemistry
• Virology
• Structural Biology

Background:

• Transmembrane proteases, Serine-2 (TMPRSS2) and TMPRSS11D, are crucial for SARS-CoV-2 and Influenza A/B virus cell entry.
• The precise biochemical mechanisms by which these proteases facilitate viral entry remain incompletely understood.

Purpose of the Study:

• To elucidate the autocleavage activation mechanisms of TMPRSS2 and TMPRSS11D.
• To investigate the structural basis of TMPRSS11D substrate recognition.
• To develop novel peptidomimetic inhibitors targeting these viral proteases.

Main Methods:

• Zymogen activation motif cleavage assays.
• Co-crystallography of TMPRSS11D with activation motifs.
• Development and testing of peptidomimetic inhibitors.
• Enzyme activity assays with nafamostat mesylate.

Main Results:

• TMPRSS2 and TMPRSS11D efficiently cleave their own zymogen activation motifs, leading to protease activation.
• Structural determination of TMPRSS11D reveals insights into its autocleavage and substrate binding.
• Novel nanomolar potency peptidomimetic inhibitors were developed for TMPRSS11D and TMPRSS2.
• Nafamostat mesylate demonstrated rapid cleavage and inactivation by TMPRSS11D.

Conclusions:

• Mechanistic insights into human protease activation and viral tropism were gained.
• The study highlights the potential and limitations of current serine protease inhibitors.
• Findings inform the development of next-generation therapeutics targeting viral proteases.