Modulation of Amyloidogenic Protein Self-Assembly Using Tethered Small Molecules

Area of Science:

• Biochemistry
• Structural Biology
• Chemical Biology

Background:

• Protein-protein interactions (PPIs) are crucial for biological functions but implicated in diseases like amyloidosis.
• Studying transient intermediates in amyloid assembly is key to understanding disease mechanisms and for drug discovery.
• Amyloid fibrils of beta-2 microglobulin (β2m) are linked to dialysis-related amyloidosis.

Purpose of the Study:

• To demonstrate the utility of covalently tethered small molecules for stabilizing amyloid oligomeric intermediates.
• To facilitate structural characterization of these stabilized intermediates.
• To investigate the role of specific oligomers in amyloid assembly pathways.

Main Methods:

• Utilizing covalently tethered small molecule fragments to trap specific oligomers during amyloid fibril formation.
• Employing the truncated variant of human beta-2 microglobulin (ΔN6) as a model system.
• Applying X-ray crystallography and Nuclear Magnetic Resonance (NMR) for structural characterization.

Main Results:

• Successfully trapped tetrameric intermediates of ΔN6 using covalent tethering.
• Demonstrated that tetramer stabilization is dependent on the tethering site and protein-fragment interaction.
• Obtained structural insights into how tetramer stabilization inhibits amyloid fibril formation.

Conclusions:

• Covalent tethering of small molecules is a powerful strategy to stabilize and study transient amyloidogenic intermediates.
• Structural characterization of trapped oligomers reveals mechanisms of inhibition for amyloid assembly.
• This approach, termed 'post-translational chemical modification,' offers a novel tool for studying biological mechanisms.