Novel tools to study West Nile virus NS3 protease activity

Area of Science:

• Virology
• Biochemistry
• Molecular Biology

Background:

• West Nile Virus (WNV) causes West Nile Fever (WNF) and severe neuroinvasive disease (WNND), with no current preventative treatments or rapid diagnostic tests.
• Current diagnostic methods for WNV infection lack speed and unambiguous assessment.
• The WNV NS3 serine protease is a key target for understanding viral activity and developing diagnostics.

Purpose of the Study:

• To develop specific and selective tools for determining West Nile Virus serine protease activity.
• To create a highly sensitive diagnostic probe for WNV infection.

Main Methods:

• Utilized combinatorial chemistry and iterative deconvolution to determine WNV serine protease substrate specificity.
• Synthesized a FRET substrate (ABZ-Ala-Lys-Gln-Arg-Gly-Gly-Thr-Tyr(3-NO2)-NH2) and characterized its kinetic parameters.
• Developed and synthesized functionalized quantum dot-based protease probes (QD) for WNV NS3 protease detection.

Main Results:

• Determined the substrate specificity of the WNV NS3 protease in non-primed and primed positions.
• Characterized a novel FRET substrate with a KM of 4.20 ± 0.32 × 10^-5 M.
• Developed a quantum dot WNV NS3 protease probe capable of detecting 0.05 nmol of enzyme, a 20-fold improvement over the optimized substrate.

Conclusions:

• The developed quantum dot probes demonstrate high sensitivity for detecting WNV NS3 protease activity.
• These probes represent a promising foundation for developing rapid and accurate diagnostic tools for West Nile Virus infection.
• Further research into WNV NS3 protease activity could lead to improved diagnostic strategies for WNV.