Protein-Templated Hit Identification through an Ugi Four-Component Reaction*

Area of Science:

• Chemical Biology
• Drug Discovery
• Biochemistry

Background:

• Kinetic target-guided synthesis (KTGS) is an efficient strategy for identifying drug leads.
• Proteins can guide the assembly of their own inhibitors from building blocks via irreversible reactions.
• Novel chemical reactions and biological targets are continuously sought for drug discovery.

Purpose of the Study:

• To pioneer an in situ Ugi reaction for KTGS.
• To identify novel inhibitors for the aspartic protease endothiapepsin.
• To identify binders for the bacterial β-sliding clamp DnaN.

Main Methods:

• Utilized an in situ Ugi reaction for protein-templated synthesis.
• Employed highly sensitive mass spectrometry to monitor reactions.
• Tested identified products for inhibitory activity against endothiapepsin and binding affinity for DnaN.

Main Results:

• Successfully identified novel Ugi products as inhibitors of endothiapepsin (low micromolar activity).
• Identified Ugi products with moderate affinity for the bacterial β-sliding clamp DnaN.
• Demonstrated background-free reaction monitoring for endothiapepsin and amplified product formation for DnaN.

Conclusions:

• The in situ Ugi reaction is an efficient and sensitive method for KTGS.
• This approach expands the scope of chemical reactions and biological targets for drug discovery.
• The methodology is broadly applicable to various drug targets.