Ultrafast excitation relaxation dynamics of lutein in solution and in the light-harvesting complexes II isolated from Arabidopsis thaliana
Ultrafast excitation relaxation dynamics of lutein in solution and in the light-harvesting complexes II isolated from Arabidopsis thaliana
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DOI：
10.1021/jp050595q
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发表时间：
2005-06-30
影响因子：
3.3
通讯作者：
Mimuro, M
中科院分区：
文献类型：
--
作者：
Akimoto, S;Yokono, M;Mimuro, M
利用飞秒时间分辨荧光光谱技术研究了生理温度下拟南芥捕光复合物II（LHC II）的超快激发弛豫动力学和能量传递过程。从叶黄素到叶绿素a的能量转移速率常数为k（ET）= 1.8-1.9 × 10 ~（13）s（-1），产率约为Phi（ET）= 0.70，而从新黄质到叶绿素a的能量转移速率常数为k（ET）= 6.5 × 10 ~（11）s（-1），产率最高为Phi（ET）= 0.09。LHC II中叶黄素的荧光各向异性衰减在初始状态下显示出大于0.4的值，并且在0.3 ps内衰减到约0.1，这表明两个叶黄素分子在LHC II中彼此相互作用。在溶液中，叶黄素的各向异性保持恒定（0.38），与时间无关，因此在S-2（1B（u））状态和S-1（2A（g））状态之间推断的新激发态不适用于溶液中的叶黄素。动力学分析清楚地解析了Chl a和Chl B分子间的能量迁移过程。在此基础上，研究了LHC Ⅱ的弛豫过程和能量转移动力学。讨论了Thaliana。
Ultrafast excitation relaxation dynamics and energy-transfer processes in the light-harvesting complex II (LHC II) of Arabidopsis thaliana were examined at physiological temperature using femtosecond time-resolved fluorescence spectroscopy. Energy transfer from lutein to Chl a proceeded with a rate constant of k(ET) = 1.8-1.9 x 10(13) s(-1) and a yield of approximately Phi(ET) = 0.70, whereas that from neoxanthin to Chl a had a rate constant of k(ET) = 6.5 x 10(11) s(-1) and a yield at the most of Phi(ET) = 0.09. Fluorescence anisotropic decay of lutein in LHC II showed a value larger than 0.4 at the initial state and decayed to approximately 0.1 in 0.3 ps, indicating that two lutein molecules interact with each other in LHC II. In solution, anisotropy of lutein remained constant (0.38) independent of time, and thus a new excited state inferred between the S-2 (1B(u)) state and the S-1 (2A(g)) state was not applicable for lutein in solution. Energy migration processes among Chl a or Chl b molecules were clearly resolved by kinetic analysis. On the basis of these results, relaxation processes and energy-transfer kinetics in LHC II of A. thaliana are discussed.