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Selection of diverse polymorphic structures from a small dynamic molecular network controlled by the environment.

ABSTRACT: The complex interplay between systems and their environment plays an important role in processes ranging from self-assembly to evolution. Polymorphism, where, from the same ingredients different products can be formed, is likely to be an important enabler for evolutionary adaptation. Environmental pressures may induce polymorphic behaviour, where different pressures result in different structural organisation. Here we show that by combining covalent and non-covalent bond formation three distinct polymorphs can emerge from the same small dynamic molecular network: vesicular aggregates, self-replicating fibres and nanoribbons, depending on the nature of the solvent environment. Additionally, a particular set of conditions allows the transient co-existence of both vesicles and fibres.

SUBMITTER: Bartolec B

PROVIDER: S-EPMC9749116 | biostudies-literature | 2022 Dec

REPOSITORIES: biostudies-literature

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Selection of diverse polymorphic structures from a small dynamic molecular network controlled by the environment.

Bartolec Boris B Kiani Armin A Beatty Meagan A MA Altay Meniz M Monreal Santiago Guillermo G Otto Sijbren S

Chemical science 20221111 48

The complex interplay between systems and their environment plays an important role in processes ranging from self-assembly to evolution. Polymorphism, where, from the same ingredients different products can be formed, is likely to be an important enabler for evolutionary adaptation. Environmental pressures may induce polymorphic behaviour, where different pressures result in different structural organisation. Here we show that by combining covalent and non-covalent bond formation three distinct ...[more]

PMID: 36545148

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Project description:BackgroundMisfolding and self-assembly of Amyloid-β (Aβ) peptides into amyloid fibrils is pathologically linked to the development of Alzheimer's disease. Polymorphic Aβ structures derived from monomers to intermediate oligomers, protofilaments, and mature fibrils have been often observed in solution. Some aggregates are on-pathway species to amyloid fibrils, while the others are off-pathway species that do not evolve into amyloid fibrils. Both on-pathway and off-pathway species could be biologically relevant species. But, the lack of atomic-level structural information for these Aβ species leads to the difficulty in the understanding of their biological roles in amyloid toxicity and amyloid formation.Methods and findingsHere, we model a series of molecular structures of Aβ globulomers assembled by monomer and dimer building blocks using our peptide-packing program and explicit-solvent molecular dynamics (MD) simulations. Structural and energetic analysis shows that although Aβ globulomers could adopt different energetically favorable but structurally heterogeneous conformations in a rugged energy landscape, they are still preferentially organized by dynamic dimeric subunits with a hydrophobic core formed by the C-terminal residues independence of initial peptide packing and organization. Such structural organizations offer high structural stability by maximizing peptide-peptide association and optimizing peptide-water solvation. Moreover, curved surface, compact size, and less populated β-structure in Aβ globulomers make them difficult to convert into other high-order Aβ aggregates and fibrils with dominant β-structure, suggesting that they are likely to be off-pathway species to amyloid fibrils. These Aβ globulomers are compatible with experimental data in overall size, subunit organization, and molecular weight from AFM images and H/D amide exchange NMR.ConclusionsOur computationally modeled Aβ globulomers provide useful insights into structure, dynamics, and polymorphic nature of Aβ globulomers which are completely different from Aβ fibrils, suggesting that these globulomers are likely off-pathway species and explaining the independence of the aggregation kinetics between Aβ globulomers and fibrils.

Dataset Information

Selection of diverse polymorphic structures from a small dynamic molecular network controlled by the environment.

Publications

Selection of diverse polymorphic structures from a small dynamic molecular network controlled by the environment.

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