Conformational dynamics is key to understanding loss-of-function of NQO1 cancer-associated polymorphisms and its...

Area of Science:

• Biochemistry
• Biophysics
• Cell Biology
• Computational Biology

Background:

• Protein dynamics are crucial for function and stability but often overlooked as a cause of genetic loss-of-function.
• Human NAD(P)H quinone oxidoreductase 1 (NQO1) is a FAD-dependent enzyme vital for activating cancer drugs and stabilizing oncosuppressors.

Purpose of the Study:

• Investigate the impact of two cancer-associated NQO1 polymorphisms (p.R139W and p.P187S) on protein dynamics and function.
• Determine how these dynamics relate to loss-of-function and potential therapeutic interventions.

Main Methods:

• Biochemical and biophysical assays to assess protein stability and ligand binding.
• Cell-based studies to evaluate protein levels in vivo.
• Computational biology tools to analyze protein dynamics at atomic and domain levels.

Main Results:

• The p.P187S polymorphism destabilizes the NQO1 dimer and increases C-terminal domain flexibility, effects partially rescued by FAD and dicoumarol.
• Altered dynamics at the dimer interface and FAD binding site correlate with reduced stability, FAD affinity, and enzyme activity.
• NQO1 protein levels in cells are primarily linked to C-terminal domain dynamics, suggesting targeted proteasomal degradation.

Conclusions:

• Protein dynamics are fundamental to understanding NQO1 loss-of-function caused by the p.P187S polymorphism.
• Ligand binding to the C-terminal domain can stabilize the enzyme in vivo.
• Targeting protein dynamics offers a potential strategy for developing new therapies to restore NQO1 function.