Wahadoszamen Md, Margalit Iris, Ara Anjue Mane, van Grondelle Rienk, Noy Dror
1] Section of Biophysics, Department of Physics and Astronomy, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands [2] Department of Physics, University of Dhaka, Dhaka 1000, Bangladesh.
1] Plant Sciences Department, Weizmann Institute of Science, Rehovot 7610001, Israel [2] Migal-Galilee Research Institute, Kiryat-Shmona 1101602, Israel.
Nat Commun. 2014 Oct 24;5:5287. doi: 10.1038/ncomms6287.
Understanding how specific protein environments affect the mechanisms of non-radiative energy dissipation within densely assembled chlorophylls in photosynthetic protein complexes is of great interest to the construction of bioinspired solar energy conversion devices. Mixing of charge-transfer and excitonic states in excitonically interacting chlorophylls was implicated in shortening excited states' lifetimes, but its relevance to active control of energy dissipation in natural systems is under considerable debate. Here we show that the degree of fluorescence quenching in two similar pairs of excitonically interacting bacteriochlorophyll derivatives is directly associated with increasing charge-transfer character in the excited state, and that the protein environment may control non-radiative dissipation by affecting the mixing of charge-transfer and excitonic states. The capability of local protein environments to determine the fate of excited states, and thereby to confer different functionalities to excitonically coupled dimers substantiates the dimer as the basic functional element of photosynthetic enzymes.
了解特定蛋白质环境如何影响光合蛋白复合物中密集组装的叶绿素内非辐射能量耗散的机制，对于构建受生物启发的太阳能转换装置具有重要意义。激子相互作用的叶绿素中电荷转移态和激子态的混合被认为与缩短激发态寿命有关，但其与自然系统中能量耗散的主动控制的相关性仍存在相当大的争议。在这里，我们表明，两对相似的激子相互作用细菌叶绿素衍生物中的荧光猝灭程度与激发态中电荷转移特性的增加直接相关，并且蛋白质环境可能通过影响电荷转移态和激子态的混合来控制非辐射耗散。局部蛋白质环境决定激发态命运的能力，从而赋予激子耦合二聚体不同的功能，证实了二聚体是光合酶的基本功能元件。
