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Updated: Mar 27, 2026
Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
A systematic molecular dynamics approach to the structural characterization of amyloid aggregation propensity of
P Chandrasekaran1, R Rajasekaran1
1Bioinformatics Division, School of Biosciences and Technology, VIT University, Vellore 632 014, Tamil Nadu, India. rrajasekaran@vit.ac.in.
Abstract:
Beta-2 microglobulin (β2m) is an amyloidogenic protein belongs to the immunoglobulin superfamily, responsible for the dialysis-related amyloidosis (DRA). Misfolding of β2m is a prerequisite to the formation of systemic amyloidosis that has an effect on the structure and function of the affected organ. The aim of our present study is to intensively explore the structural characterization of amyloid aggregation propensity of recently identified natural mutation D76N by applying the classical molecular dynamics (MD) approach. The MD result revealed that mutant D76N exhibited a wide variation in the evolutionarily conserved secondary structure profile. Due to an unsatisfied position of main chain donor/acceptor atoms that unable to form essential hydrogen bonds resulted to cause misfolding of mutant D76N by disrupting the local folding of β-strands and turn region. Analysis of time evolution of various structural properties, especially those of the functionally important residues: aggregation determining, initiating, and gatekeeper residues gave some possible insights into the structural characteristics of the disease mutant D76N. In a nutshell, compared to the wild-type β2m, aggregation promoting propensity of mutant D76N has established a long β-strand D owing to an inward movement of residue, Asp(53). Besides, aggregation forming characteristic of the DE loop in mutant D76N showed greater flexibility along the first principal eigenvector that favored to enhance an unusual conformational dynamics may lead toward self-aggregation and amyloid fibrils.
Insights
The D76N mutation in beta-2 microglobulin (β2m) causes protein misfolding and enhances amyloid aggregation propensity. This structural change in β2m may contribute to dialysis-related amyloidosis (DRA).
Area of Science:
- Biochemistry
- Structural Biology
- Computational Biophysics
Background:
- Beta-2 microglobulin (β2m) is an amyloidogenic protein linked to dialysis-related amyloidosis (DRA).
- Protein misfolding is a critical step in the development of systemic amyloidosis, impacting organ structure and function.
Purpose of the Study:
- To investigate the structural characteristics and amyloid aggregation propensity of the natural D76N mutation in β2m.
- To understand the molecular mechanisms underlying the D76N mutation's role in amyloid formation using molecular dynamics.
Main Methods:
- Classical molecular dynamics (MD) simulations were employed to study the structural behavior of the D76N mutant β2m.
- Analysis focused on secondary structure profiles, hydrogen bonding, and the dynamics of functionally important residues.
Main Results:
- The D76N mutant showed significant variations in its conserved secondary structure profile compared to wild-type β2m.
- Misfolding in D76N was attributed to disrupted hydrogen bonding, affecting β-strands and turn regions.
- The D76N mutation promoted aggregation by stabilizing a long β-strand D and increasing the flexibility of the DE loop, favoring unusual conformational dynamics.
Conclusions:
- The D76N mutation in β2m enhances its propensity for amyloid aggregation through specific structural alterations.
- These findings provide insights into the molecular basis of D76N-related amyloidosis.
- The study highlights the role of conformational dynamics in the self-aggregation of β2m mutants.
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