Chirality-Assisted Ring-Like Aggregation of Aβ(1–40) at Liquid–Solid Interfaces: A Stereoselective Two-Step Assembly Process†
This work was supported by National Natural Science Foundation of China (91127027, 51173142, 21105078), the China National Funds for Distinguished Young Scientists (51325302), the Major State Basic Research Development Program of China (973 Program: 2013CB933002), the Program for Changjiang Scholars and Innovative Research Team in University (IRT1169), and the Program of Introducing Talents of Discipline to Universities (B13035).
Abstract
Stereoselektive Oberflächen: Amyloid Aβ(1–40) bildet auf mit N-Isobutyryl-L-cystein (L-NIBC) modifizierten Goldoberflächen bei niedriger Konzentration ringförmige Aggregate, auf D-NIBC-modifizierten Oberflächen hingegen stabförmige Aggregate. Die unterschiedliche Ausrichtung der β-Haarnadelstruktur ist das Resultat der stereoselektiven Erkennung durch die chirale Oberfläche, verstärkt durch elektrostatische Wechselwirkungen.
Abstract
Molecular chirality is introduced at liquid–solid interfaces. A ring-like aggregation of amyloid Aβ(1–40) on N-isobutyryl-L-cysteine (L-NIBC)-modified gold substrate occurs at low Aβ(1–40) concentration, while D-NIBC modification only results in rod-like aggregation. Utilizing atomic force microscope controlled tip-enhanced Raman scattering, we directly observe the secondary structure information for Aβ(1–40) assembly in situ at the nanoscale. D- or L-NIBC on the surface can guide parallel or nonparallel alignment of β-hairpins through a two-step process based on electrostatic-interaction-enhanced adsorption and subsequent stereoselective recognition. Possible electrostatic interaction sites (R5 and K16) and a chiral recognition site (H14) of Aβ(1–40) are proposed, which may provide insight into the understanding of this effect.





