Jason Zhu, Adam G Kreutzer, Zhiwei Liu, Xingyue Li, Sabrina M Richter, Vojislava Pophristic, James S Nowick
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引用次数: 0
Abstract
The supramolecular assembly of amyloid-β into soluble oligomers is critical Alzheimer's disease (AD) progression. Soluble Aβ oligomers have emerged as neurotoxic species involved in AD progression and some Aβ oligomers are thought to be composed of β-hairpins. In this work, we report the X-ray crystallographic and solution-phase assembly of a macrocyclic β-hairpin peptide that mimics a β-hairpin formed by Aβ16-36. In the crystal lattice, the peptide assembles into a symmetric hexamer composed of two identical triangular trimers. In aqueous solution, the peptide assembles to form an asymmetric hexamer. 1H NMR, TOCSY, and 1H,15N HSQC experiments establish that the asymmetric hexamer contains two different species, A and B. 15N-edited NOESY reveals that species A is a cylindrin-like trimer and species B is a triangular trimer that collectively constitute the asymmetric hexamer. Diffusion-ordered NMR spectroscopy (DOSY) suggests that two asymmetric hexamers further assemble to form a dodecamer. NMR-guided molecular mechanics and molecular dynamics studies provide a model for the asymmetric hexamer and suggest how two asymmetric hexamers can form a dodecamer. Solution-phase NMR studies of analogues show that intermolecular hydrogen bonding and the formation of a hydrophobic core help stabilize the asymmetric hexamer. These NMR and crystallographic studies illustrate how an Aβ β-hairpin peptide can assemble to form different well-defined oligomers in the crystal state and in aqueous solution, providing a deeper understanding of the heterogeneity of Aβ oligomers and new structural models of Aβ oligomers composed of Aβ β-hairpins.
期刊介绍:
Organic & Biomolecular Chemistry is an international journal using integrated research in chemistry-organic chemistry. Founded in 2003 by the Royal Society of Chemistry, the journal is published in Semimonthly issues and has been indexed by SCIE, a leading international database. The journal focuses on the key research and cutting-edge progress in the field of chemistry-organic chemistry, publishes and reports the research results in this field in a timely manner, and is committed to becoming a window and platform for rapid academic exchanges among peers in this field. The journal's impact factor in 2023 is 2.9, and its CiteScore is 5.5.