Picosecond Dynamics of a Small Molecule in Its Bound State with an Intrinsically Disordered Protein

Area of Science:

• Biochemistry
• Structural Biology
• Drug Discovery

Background:

• Intrinsically disordered proteins (IDPs) lack stable structures, complicating drug development.
• IDPs are implicated in various diseases, including cancer and viral infections.
• Targeting IDPs is challenging due to their dynamic nature and absence of traditional binding sites.

Purpose of the Study:

• To investigate the interaction between small molecules and IDPs.
• To demonstrate that IDPs can bind small molecules dynamically.
• To explore novel therapeutic strategies for IDP-related diseases.

Main Methods:

• Utilized 19F nuclear magnetic resonance (NMR) spectroscopy.
• Employed 19F transverse spin-relaxation measurements.
• Analyzed rotational correlation times (τc) of a small molecule.

Main Results:

• Discovered 5-fluoroindole interacts with hepatitis C virus non-structural protein 5A (NS5A).
• Determined a dissociation constant (Kd) of 260 ± 110 μM for the interaction.
• Observed dynamic binding with minimal change in rotational correlation time (27.0 ± 1.3 ps free vs. 46 ± 10 ps bound).

Conclusions:

• Small molecules can engage with IDPs through dynamic interactions.
• Challenges the notion that IDPs are undruggable.
• Opens new avenues for developing therapeutics targeting intrinsically disordered proteins.