Basic pH-induced modification of excitation-energy dynamics in fucoxanthin chlorophyll a/c-binding proteins isolated from a pinguiophyte, Glossomastix chrysoplasta
Basic pH-induced modification of excitation-energy dynamics in fucoxanthin chlorophyll a/c-binding proteins isolated from a pinguiophyte, Glossomastix chrysoplasta
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碱性 pH 诱导的岩藻黄质叶绿素 A/C 结合蛋白的激发能动力学修饰，从 Pinguiophyte Glossomastix chrysoplasta 中分离出来
DOI：
10.1016/j.bbabio.2020.148306
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Akimoto Seiji
中科院分区：
文献类型：
--
作者：
Nagao Ryo;Yokono Makio;Ueno Yoshifumi;Kato Ka-Ho;Tsuboshita Naoki;Shen Jian-Ren;Akimoto Seiji
光合生物具有多样化的光收集复合物（lhc）来有效地收集太阳能，从而获得其生态位。本文报道了从一种海洋植物中分离得到的岩藻黄质叶绿素/c-结合蛋白（FCP）复合物的生化和光谱特征。棘球菌FCP在SDS-PAGE中显示一个亚基带，在透明原生PAGE中显示一个分子量在66 kDa左右的蛋白复合物带。通过HPLC分析，FCP含有叶绿素、岩藻黄质和紫黄质。为了阐明FCP中的激发-能量弛豫过程，我们测量了FCP在77 K时适应pH 5.0、6.5和8.0的时间分辨荧光光谱。与pH 6.5相比，pH 5.0和8.0下的荧光曲线显示出更短的寿命成分。荧光衰减相关（FDA）光谱揭示了pH 5.0和8.0下的快速衰减组分；270 -ps和160-ps的FDA光谱仅在pH 5.0和8.0时发生荧光衰减。此外，在碱性pH条件下，能量传递途径发生改变，时间常数为几十皮秒，而在酸性pH条件下则没有变化。这些发现为FCP家族以及光合作用lhc的ph依赖性能量转移和能量猝灭机制提供了新的见解。
Photosynthetic organisms have diversified light-harvesting complexes (LHCs) to collect solar energy efficiently, leading to an acquisition of their ecological niches. Herein we report on biochemical and spectroscopic characterizations of fucoxanthin chlorophylla/c-binding protein (FCP) complexes isolated from a marine pinguiophyteGlossomastix chrysoplasta. The pinguiophyte FCP showed one subunit band in SDS-PAGE and one protein-complex band with a molecular weight at around 66 kDa in clear-native PAGE. By HPLC analysis, the FCP possesses chlorophyllsaandc, fucoxanthin, and violaxanthin. To clarify excitation-energy-relaxation processes in the FCP, we measured time-resolved fluorescence spectra at 77 K of the FCP adapted to pH 5.0, 6.5, and 8.0. Fluorescence curves measured at pH 5.0 and 8.0 showed shorter lifetime components compared with those at pH 6.5. The rapid decay components at pH 5.0 and 8.0 are unveiled by fluorescence decay-associated (FDA) spectra; fluorescence decays occur in the 270 and 160-ps FDA spectra only at pH 5.0 and 8.0, respectively. In addition, energy-transfer pathways with time constants of tens of picoseconds are altered under the basic pH condition but not the acidic pH condition. These findings provide novel insights into pH-dependent energy-transfer and energy-quenching machinery in not only FCP family but also photosynthetic LHCs.