Nanoscale & Quantum Phenomena Institute and Physics & Astronomy Department, Ohio University , Athens, Ohio 45701, United States.
ACS Nano. 2018 Jan 23;12(1):217-225. doi: 10.1021/acsnano.7b05841. Epub 2018 Jan 11.
Carotenoids and chlorophyll are essential parts of plant leaves and are involved in photosynthesis, a vital biological process responsible for the origin of life on Earth. Here, we investigate how β-carotene and chlorophyll-a form mixed molecular phases on a Au(111) surface using low-temperature scanning tunneling microscopy and molecular manipulation at the single-molecule level supported by density functional theory calculations. By isolating individual molecules from nanoscale molecular clusters with a scanning tunneling microscope tip, we are able to identify five β-carotene conformations including a structure exhibiting a three-dimensional conformation. Furthermore, molecular resolution images enable direct visualization of β-carotene/chlorophyll-a clsuters, with intimate structural details highlighting how they pair: β-carotene preferentially positions next to chlorophyll-a and induces switching of chlorophyll-a from straight to several bent tail conformations in the molecular clusters.
类胡萝卜素和叶绿素是植物叶片的重要组成部分，参与光合作用，这是地球上生命起源的关键生物过程。在这里，我们使用低温扫描隧道显微镜和分子操纵，并结合密度泛函理论计算，研究了β-胡萝卜素和叶绿素-a 在 Au(111)表面如何形成混合分子相。通过用扫描隧道显微镜针尖从纳米级分子簇中分离单个分子，我们能够识别五种β-胡萝卜素构象，包括一种具有三维构象的结构。此外，分子分辨率图像能够直接观察β-胡萝卜素/叶绿素-a 簇，其结构细节突出了它们的配对方式：β-胡萝卜素优先位于叶绿素-a 旁边，并诱导叶绿素-a 在分子簇中从直线到几个弯曲的尾部构象发生转变。
