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Updated: Feb 3, 2026

Interactions with and Membrane Permeabilization of Brain Mitochondria by Amyloid Fibrils
Published on: September 28, 2019
Repulsive interaction induces fibril formation and their growth
Suparna Khatun1, Kumari Shikha2, Agneyo Ganguly3
1Biophysics Laboratory, Department of Physics, Indian Institute of Technology, Kharagpur 721302, India.
Type-II diabetes involves amylin protein misfolding into amyloid fibrils. We observed protein interactions shift from repulsive to attractive, driving fibril formation and growth, revealing key aggregation mechanisms.
Area of Science:
- Biochemistry
- Structural Biology
- Biophysics
Background:
- Type-II diabetes is linked to amylin protein misfolding and amyloid fibril formation.
- The precise mechanism of amyloid fibril conversion remains poorly understood.
- Amylin aggregation is a critical factor in the pathogenesis of type-II diabetes.
Purpose of the Study:
- To investigate the aggregation and fibril growth kinetics of amylin protein.
- To elucidate the transition in protein-protein interactions during fibril formation.
- To characterize the structural changes and growth mechanisms of amylin fibrils under varying conditions.
Main Methods:
- Laser light scattering technique to measure the second virial coefficient (A2) and shape factor (ρ).
- Analytical and high-resolution Transmission Electron Microscopy (TEM) for structural imaging.
- Kinetic analysis of amylin aggregation and fibril elongation.
Main Results:
- Observed a switch from repulsive (positive A2) to attractive (negative A2) protein interactions over time, promoting fibril formation.
- Light scattering indicated a structural transition from coil-like to rod-like amylin.
- TEM imaging revealed both rod-like and sheet-like fibril growth, with hydrogen bonding mediating nucleation, elongation, and stacking.
Conclusions:
- The transition from repulsive to attractive protein interactions is a key driver of amylin amyloid fibril formation in type-II diabetes.
- Amylin fibrils exhibit complex growth patterns, including rod-like and sheet-like structures.
- Hydrogen bonding plays a crucial role in the structural organization and growth of amylin fibrils.
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