Structural Interaction of Apolipoprotein A-I Mimetic Peptide with Amyloid-β Generates Toxic Hetero-oligomers. Issue 4 (14th February 2020)

• Record Type: Journal Article
• Authors: Sahoo, Bikash Ranjan; Bekier, Michael E.; Liu, Zichen; Kocman, Vojc; Stoddard, Andrea K.; Anantharamaiah, G.M.; Nowick, James; Fierke, Carol A.; Wang, Yanzhuang; Ramamoorthy, Ayyalusamy
• Is Part Of: Journal of molecular biology. Volume 432:Issue 4(2020)
• Page Start: 1020
• Page End: 1034
• Publication Date: 2020-02-14
• Subjects: amyloid β -- Alzheimer's disease -- apolipoproteins -- amyloid oligomers -- protein misfolding and aggregation; Molecular biology -- Periodicals; Biology -- Periodicals; Biochemistry -- Periodicals; Bacteriology -- Periodicals; Molecular Biology -- Periodicals; Biochemistry -- Periodicals; Biologie moléculaire -- Périodiques; Biologie -- Périodiques; Biochimie -- Périodiques; Moleculaire biologie; Biochemistry; Biology; Molecular biology; Periodicals; 572.805
• DOI: 10.1016/j.jmb.2019.12.005
• Languages: English
• ISSNs: 0022-2836

Abstract

Abstract: Apolipoproteins are involved in pathological conditions of Alzheimer's disease (AD), and it has been reported that truncated apolipoprotein fragments and β-amyloid (Aβ) peptides coexist as neurotoxic heteromers within the plaques. Therefore, it is important to investigate these complexes at the molecular level to better understand their properties and roles in the pathology of AD. Here, we present a mechanistic insight into such heteromerization using a structurally homologue apolipoprotein fragment of apoA-I (4F) complexed with Aβ(M1-42) and characterize their toxicity. The 4F peptide slows down the aggregation kinetics of Aβ(M1-42) by constraining its structural plasticity. NMR and CD experiments identified 4F-Aβ(M1-42) heteromers comprised of unstructured Aβ(M1-42) and helical 4F. A uniform two-fold reduction in 15 N/ 1 H NMR signal intensities of Aβ(M1-42) with no observable chemical shift perturbation indicated the formation of a large complex, which was further confirmed by diffusion NMR experiments. Microsecond-scale atomistic molecular dynamics simulations showed that 4F interaction with Aβ(M1-42) is electrostatically driven and induces unfolding of Aβ(M1-42). Neurotoxicity profiling of Aβ(M1-42) complexed with 4F confirms a significant reduction in cell viability and neurite growth. Thus, the molecular architecture of heteromerization between 4F and Aβ(M1-42) discovered in this study provides evidence toward our understanding of the role of apolipoproteins or their truncated fragments in exacerbating AD pathology. Graphical abstract: Image 1 Highlights: Structural model for an oligomer of Aβ(M1-42) and ApoA-I mimetic peptide is reported. Aβ(M1-42)-4F oligomer exhibits a significant reduction in cell viability and neurite growth. 4F peptide electrostatically interacts and induces unfolding of Aβ(M1-42).