Exploring advanced methodologies for NS5 methyltransferase targeted drug discovery.

Area of Science:

• Biochemistry
• Virology
• Drug Discovery

Background:

• Emerging viral pathogens necessitate targeted antiviral therapies.
• The Dengue virus NS5 methyltransferase is crucial for viral RNA capping and immune evasion, making it a therapeutic target.
• Limited availability of robust assays has hindered the discovery of small-molecule inhibitors for this enzyme.

Purpose of the Study:

• To address the need for effective Dengue virus NS5 methyltransferase inhibitors.
• To comparatively evaluate three orthogonal methodologies for inhibitor identification and characterization.
• To establish an integrated screening strategy for developing novel antiviral agents.

Main Methods:

• Synthesis of 30 S-adenosylhomocysteine analogs using copper-catalyzed azide-alkyne cycloaddition.
• Screening inhibitors using fluorescence polarization (ligand displacement), NMR titration (residue-specific interactions), and acoustic mass spectrometry (label-free enzymatic assay).
• Comparative analysis of assay performance and inhibitor potency rankings.

Main Results:

• Consistent potency rankings were observed across all three orthogonal assay platforms.
• Fluorescence polarization enabled high-throughput screening for initial inhibitor triaging.
• NMR provided crucial structural insights into ligand-enzyme interactions, and acoustic mass spectrometry confirmed functional inhibition.
• The integrated approach validated the rational development of NS5 methyltransferase inhibitors.

Conclusions:

• An integrated, modular screening strategy effectively identifies and characterizes Dengue virus NS5 methyltransferase inhibitors.
• This approach facilitates the rational design of potent antiviral compounds.
• The methodology is adaptable for targeting related RNA-capping enzymes in other viruses or organisms.