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<p>Non-specific disruption of cellular membranes induced by amyloidogenic aggregation of β-amyloid (Aβ) peptides remains a viable cytotoxicity mechanism in Alzheimer’s disease (AD). Obtaining structural information about the intermediate states of Aβ-membrane systems and their molecular interactions is challenging due to their heterogeneity and low abundance. Here, we systematically study the molecular interactions of membrane-associated Aβ<sub>1-42</sub> peptides using solid-state nuclear magnetic resonance (ssNMR) spectroscopy, focusing on the primary nucleation phase of the fibrillation process. Compared to the less pathogenic Aβ<sub>1-40</sub> peptide, Aβ<sub>1-42</sub> forms smaller oligomers prior to fibrillation, as evidenced by a higher overall population of lipid-proximity peptides. Aβ<sub>1-42</sub> also exhibits more pronounced residue-specific contacts with phospholipid headgroups compared to Aβ<sub>1-40</sub>, with multiple lipid-proximity segments throughout the entire primary sequence. The segments involved in initial inter-strand assembly overlap with those located near the lipid headgroups in Aβ<sub>1-42</sub>, whereas these two segments are distinct in Aβ<sub>1-40</sub>. ssNMR spectroscopy with sensitivity enhanced by Dynamic nuclear polarization (DNP) confirmed local secondary structural convergence during the nucleation process of Aβ<sub>1-42</sub> and the presence of long-range tertiary contacts at early stages of nucleation. Overall, our results provide a molecular-level understanding of the Aβ<sub>1-42</sub> nucleation process in a membrane-like environment and its membrane-disrupting intermediates. The comparison between Aβ<sub>1-42</sub> and Aβ<sub>1-40</sub> explains its higher cytotoxicity from the perspective of membrane disruption.</p>

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Structural convergence and membrane interactions of Aβ1-42 along the primary nucleation process studied by solid state NMR

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年4月30日

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  • Maurine K. Kengwerere,
  • June M. Kenyaga,
  • Peng Xiao,
  • Shubha S. Gunaga,
  • Faith J. Scott,
  • Xyomara Wutoh-Hughes,
  • James Wang,
  • Brian Lum,
  • Yan Sun,
  • Frederic Mentink-Vigier,
  • Tuo Wang,
  • Wei Qiang

摘要

Non-specific disruption of cellular membranes induced by amyloidogenic aggregation of β-amyloid (Aβ) peptides remains a viable cytotoxicity mechanism in Alzheimer’s disease (AD). Obtaining structural information about the intermediate states of Aβ-membrane systems and their molecular interactions is challenging due to their heterogeneity and low abundance. Here, we systematically study the molecular interactions of membrane-associated Aβ1-42 peptides using solid-state nuclear magnetic resonance (ssNMR) spectroscopy, focusing on the primary nucleation phase of the fibrillation process. Compared to the less pathogenic Aβ1-40 peptide, Aβ1-42 forms smaller oligomers prior to fibrillation, as evidenced by a higher overall population of lipid-proximity peptides. Aβ1-42 also exhibits more pronounced residue-specific contacts with phospholipid headgroups compared to Aβ1-40, with multiple lipid-proximity segments throughout the entire primary sequence. The segments involved in initial inter-strand assembly overlap with those located near the lipid headgroups in Aβ1-42, whereas these two segments are distinct in Aβ1-40. ssNMR spectroscopy with sensitivity enhanced by Dynamic nuclear polarization (DNP) confirmed local secondary structural convergence during the nucleation process of Aβ1-42 and the presence of long-range tertiary contacts at early stages of nucleation. Overall, our results provide a molecular-level understanding of the Aβ1-42 nucleation process in a membrane-like environment and its membrane-disrupting intermediates. The comparison between Aβ1-42 and Aβ1-40 explains its higher cytotoxicity from the perspective of membrane disruption.