Effect of Post-Translational Modifications and Mutations on Amyloid-β Fibrils Dynamics at N Terminus
| Autor: | Brian Kierl, Zhi-Wen Hu, Dmitry Ostrovsky, Wei Qiang, Dan F. Au, Riqiang Fu, Liliya Vugmeyster |
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| Rok vydání: | 2019 |
| Předmět: |
0303 health sciences
Amyloid beta-Peptides Amyloid β Chemistry Mutant Biophysics Articles Molecular Dynamics Simulation Fibril N-terminus Zinc 03 medical and health sciences 0302 clinical medicine Protein Domains Mutation Bound state Posttranslational modification Phosphorylation Protein Multimerization Protein Processing Post-Translational Conformational ensembles 030217 neurology & neurosurgery 030304 developmental biology |
| Zdroj: | Biophys J |
| ISSN: | 0006-3495 |
| DOI: | 10.1016/j.bpj.2019.09.004 |
| Popis: | We investigate the variability in the dynamics of the disordered N-terminal domain of amyloid-β fibrils (Aβ), comprising residues 1–16 of Aβ(1–40), due to post-translational modifications and mutations in the β-bend regions known to modulate aggregation properties. Using (2)H static solid-state NMR approaches, we compare the dynamics in the wild-type Aβ fibrils in the threefold symmetric polymorph with the fibrils from three post-translational modification sequences: isoaspartate-D7, the phosphorylation of S8, and an N-terminal truncation ΔE3. Additional comparisons are made with the mutants in the β-bend region (residues 21–23) corresponding to the familial Osaka E22Δ deletion and D23N Iowa mutation. We also include the aggregates induced by Zn(2+) ions. The dynamics are probed at the F4 and G9 positions. The main motional model involves two free states undergoing diffusion and conformational exchanges with the bound state in which the diffusion is quenched because of transient interactions involving fibril core and other intrastrand contacts. The fraction of the bound state increases in a sigmoidal fashion with a decrease in temperature. There is clear variability in the dynamics: the phosphorylation of S8 variant is the most rigid at the G9 site in line with structural studies, the ΔE3 fibrils are more flexible at the G9 site in line with the morphological fragmentation pattern, the Zn-induced aggregates are the most mobile, and the two β-bend mutants have the strongest changes at the F4 site toward higher rigidity. Overall, the changes underlie the potential role of conformational ensembles in setting the stage for aggregation-prone states. |
| Databáze: | OpenAIRE |
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