Tuning antenna function through hydrogen bonds to chlorophyll a
Tuning antenna function through hydrogen bonds to chlorophyll a
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DOI：
10.1016/j.bbabio.2019.148078
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发表时间：
2020-04-01
影响因子：
4.3
通讯作者：
Robert, Bruno
中科院分区：
文献类型：
--
作者：
Llansola-Portoles, Manuel J.;Li, Fei;Robert, Bruno
我们描述了一种调节光合天线蛋白中叶绿素a（Chl-a）分子功能特性的分子机制。通过低温吸收和共振拉曼光谱探测高等植物中光系统II的捕光复合物-特别是用α-或β-十二烷基麦芽糖苷纯化的LHCII，沿着CP 29。我们发现，氢键的共轭酮羰基的蛋白质结合的叶绿素-a调谐其Sorel和Q（y）吸收跃迁的能量，诱导红移的强度成正比的氢键参与。Chls-a与非氢键的酮C13（1）基团呈现出最蓝的吸收带，而两个跃迁随着氢键强度的增加而逐渐红移-在Q（y）和Sorel带分别高达382和605 cm（-1）。因此，这些氢键调节捕光蛋白中Chl-a的位点能量，决定（至少部分地）这些复合物中能量转移事件的级联。
We describe a molecular mechanism tuning the functional properties of chlorophyll a (Chl-a) molecules in photosynthetic antenna proteins. Light-harvesting complexes from photosystem II in higher plants - specifically LHCII purified with alpha- or beta-dodecyl-maltoside, along with CP29 - were probed by low-temperature absorption and resonance Raman spectroscopies. We show that hydrogen bonding to the conjugated keto carbonyl group of protein-bound Chl-a tunes the energy of its Sorel and Q(y) absorption transitions, inducing red-shifts that are proportional to the strength of the hydrogen bond involved. Chls-a with non-H-bonded keto C13(1) groups exhibit the blue-most absorption bands, while both transitions are progressively red-shifted with increasing hydrogen-bonding strength - by up 382 & 605 cm(-1) in the Q(y) and Sorel band, respectively. These hydrogen bonds thus tune the site energy of Chl-a in light-harvesting proteins, determining (at least in part) the cascade of energy transfer events in these complexes.