美国加州大学Caram, Justin R.团队报了J聚集螺旋捕光纳米管的近原子分辨率结构。相关研究成果于2024年2月5日发表在国际顶尖学术期刊《自然—化学》。

冷冻电子显微镜为生物自组装带来了一场分辨率革命，但合成超分子材料只有少数结构得到了分析。特别是对于发色团超分子聚集体，高分辨率结构对于理解和调节长程激子耦合是必要的。

该文中，研究人员提出了一种3.3结构的原型仿生光捕获纳米管，该纳米管衍生自两亲性菁染料（C8S3-Cl）。螺旋3D重建直接可视化控制激子性质的发色团堆积。该结构清楚地显示了砖层排列，修正了之前假设的人字形排列。此外，确定了一种新的非生物超分子基序——互锁磺酸盐——这可能是光捕获纳米管的滑移堆积和J聚集性质的原因。

该项工作展示了独立获得的原生态结构如何补充光物理测量，并将使人们能够准确理解（激子）结构-功能特性，为光捕获发色团聚集体的材料设计提供信息。

附：英文原文

Title: Near-atomic-resolution structure of J-aggregated helical light-harvesting nanotubes

Author: Deshmukh, Arundhati P., Zheng, Weili, Chuang, Chern, Bailey, Austin D., Williams, Jillian A., Sletten, Ellen M., Egelman, Edward H., Caram, Justin R.

Issue&Volume: 2024-02-05

Abstract: Cryo-electron microscopy has delivered a resolution revolution for biological self-assemblies, yet only a handful of structures have been solved for synthetic supramolecular materials. Particularly for chromophore supramolecular aggregates, high-resolution structures are necessary for understanding and modulating the long-range excitonic coupling. Here, we present a 3.3 structure of prototypical biomimetic light-harvesting nanotubes derived from an amphiphilic cyanine dye (C8S3-Cl). Helical 3D reconstruction directly visualizes the chromophore packing that controls the excitonic properties. Our structure clearly shows a brick layer arrangement, revising the previously hypothesized herringbone arrangement. Furthermore, we identify a new non-biological supramolecular motif—interlocking sulfonates—that may be responsible for the slip-stacked packing and J-aggregate nature of the light-harvesting nanotubes. This work shows how independently obtained native-state structures complement photophysical measurements and will enable accurate understanding of (excitonic) structure–function properties, informing materials design for light-harvesting chromophore aggregates.

DOI: 10.1038/s41557-023-01432-6

Source: https://www.nature.com/articles/s41557-023-01432-6