首页    期刊浏览 2024年12月03日 星期二
登录注册

文章基本信息

  • 标题:How reduced excitonic coupling enhances light harvesting in the main photosynthetic antennae of diatoms
  • 本地全文:下载
  • 作者:Tjaart P. J. Krüger ; Pavel Malý ; Maxime T. A. Alexandre
  • 期刊名称:Proceedings of the National Academy of Sciences
  • 印刷版ISSN:0027-8424
  • 电子版ISSN:1091-6490
  • 出版年度:2017
  • 卷号:114
  • 期号:52
  • 页码:E11063-E11071
  • DOI:10.1073/pnas.1714656115
  • 语种:English
  • 出版社:The National Academy of Sciences of the United States of America
  • 摘要:Strong excitonic interactions are a key design strategy in photosynthetic light harvesting, expanding the spectral cross-section for light absorption and creating considerably faster and more robust excitation energy transfer. These molecular excitons are a direct result of exceptionally densely packed pigments in photosynthetic proteins. The main light-harvesting complexes of diatoms, known as fucoxanthin–chlorophyll proteins (FCPs), are an exception, displaying surprisingly weak excitonic coupling between their chlorophyll (Chl) a ’s, despite a high pigment density. Here, we show, using single-molecule spectroscopy, that the FCP complexes of Cyclotella meneghiniana switch frequently into stable, strongly emissive states shifted 4–10 nm toward the red. A few percent of isolated FCPa complexes and ∼20% of isolated FCPb complexes, on average, were observed to populate these previously unobserved states, percentages that agree with the steady-state fluorescence spectra of FCP ensembles. Thus, the complexes use their enhanced sensitivity to static disorder to increase their light-harvesting capability in a number of ways. A disordered exciton model based on the structure of the main plant light-harvesting complex explains the red-shifted emission by strong localization of the excitation energy on a single Chl a pigment in the terminal emitter domain due to very specific pigment orientations. We suggest that the specific construction of FCP gives the complex a unique strategy to ensure that its light-harvesting function remains robust in the fluctuating protein environment despite limited excitonic interactions.
  • 关键词:photosynthetic excitons ; single-molecule spectroscopy ; light-harvesting complex ; fucoxanthin–chlorophyll protein ; protein disorder
国家哲学社会科学文献中心版权所有