Visualizing single-molecule conformational transition and binding dynamics of intrinsically disordered proteins

Area of Science:

• Biophysics
• Nanotechnology
• Molecular Biology

Background:

• Intrinsically disordered proteins (IDPs) are vital in cellular functions but their dynamic nature poses challenges for study.
• IDPs are promising drug targets, yet understanding their behavior is limited.

Purpose of the Study:

• To develop a single-molecule nanocircuit for label-free, in situ, long-term monitoring of IDPs.
• To investigate the folding and interaction mechanisms of the c-Myc disordered domain with Max and small molecule inhibitors.

Main Methods:

• Construction of a silicon nanowire field-effect transistor (SiNW-FET) nanocircuit.
• Functionalization of the SiNW-FET with an individual c-Myc bHLH-LZ domain.
• Ultrasensitive real-time monitoring of c-Myc self-folding/unfolding and interactions.

Main Results:

• Observed the dynamic self-folding/unfolding process of individual c-Myc molecules.
• Captured a stable encounter intermediate ensemble during c-Myc folding.
• Quantified c-Myc/Max and c-Myc/inhibitor interactions, yielding dissociation constants consistent with ensemble methods.

Conclusions:

• The developed nanotechnology offers a powerful tool for studying IDP conformation and interactions at the single-molecule level.
• This approach provides insights into IDP binding and folding mechanisms, crucial for drug discovery targeting IDPs.