Evaluating the effect of mutations and ligand binding on transthyretin homotetramer dynamics

Area of Science:

• Biochemistry
• Structural Biology
• Computational Biology

Background:

• Transthyretin (TTR) amyloidosis involves the dissociation of the native TTR homotetramer, initiating fibril formation.
• Specific point mutations can destabilize TTR's quaternary structure, promoting amyloidogenesis.
• Drug development for TTR amyloidosis focuses on compounds that bind to and stabilize the TTR tetramer.

Purpose of the Study:

• To identify critical positions within the TTR tetramer that influence its dynamical stability.
• To analyze how mutations at these positions affect TTR tetramer equilibrium dynamics.
• To evaluate the impact of various compounds on TTR-ligand binding and tetramer stabilization.

Main Methods:

• Normal mode analysis to assess TTR tetramer dynamics.
• Simulation of local perturbations to study TTR response.
• Analysis of TTR-ligand binding interactions and their effect on vibrations.

Main Results:

• Key positions sustaining TTR tetramer stability are primarily located at β-strands E and F and the EF-loop.
• Mutations at the monomer-monomer interface significantly alter TTR tetramer dynamics, increasing amyloidosis risk.
• Mutations at dimer-dimer interfaces or the T4 hormone binding site also destabilize the TTR tetramer.

Conclusions:

• The monomer-monomer interface is a vulnerable region for mutations leading to TTR amyloidosis.
• Understanding TTR's dynamical stability and ligand interactions is vital for developing effective therapies.
• Computational analysis provides insights into TTR stabilization mechanisms and drug efficacy.