Clarifying and illustrating the electronic energy transfer pathways in trimeric and hexameric aggregation state of cyanobacteria allophycocyanin within the framework of Förster theory
Clarifying and illustrating the electronic energy transfer pathways in trimeric and hexameric aggregation state of cyanobacteria allophycocyanin within the framework of Förster theory
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DOI：
10.1002/jcc.23770
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发表时间：
2015-01
影响因子：
3
通讯作者：
Yanliang Ren;Osama Melhem;Yongjiang Li;Bo Chi;Xinya Han;Hao Zhu;Lingling Feng;Jian Wan;Xin Xu
中科院分区：
文献类型：
--
作者：
Yanliang Ren;Osama Melhem;Yongjiang Li;Bo Chi;Xinya Han;Hao Zhu;Lingling Feng;Jian Wan;Xin Xu
在Förster理论的框架下，研究了蓝细菌异藻蓝蛋白（APC）三聚体和六聚体的电子激发能传递途径。在时间依赖密度泛函理论（TDDFT）的理论水平上计算了APC中藻蓝胆素（pcb）的相关物理量（即激发能、振子强度和跃迁偶极矩）。为了估计蛋白质环境对上述计算物理量的影响，在TDDFT理论水平上用极化连续体模型近似考虑了远距离相互作用，并考虑了多氯联苯周围天冬氨酸残留引起的短程相互作用。在Förster模型框架下，在TDDFT/B3LYP/ 6-31 +G*理论水平下，APC三聚体的最短能量传递时间约为0.10 ps， APC单体的最短能量传递时间约为170 ps，这与实验结果一致，APC三聚体的寿命非常快，为0.43-0.44 ps，而其单体则没有相应的寿命。这些结果表明，Sharkov等人确定的APC三聚体的寿命为0.43-0.44 ps，这很可能归因于α1‐84↔β3‐84 （0.23 ps）、β1‐84↔α2‐84 （0.11 ps）或β2‐84↔α3‐84 （0.10 ps）的能量传递。到目前为止，还没有两种APC三聚体之间的实验或理论能量转移率的报道，我们的计算预测APC三聚体之间的主要能量转移途径可能发生在α3‐84在一个三聚体到α5‐84相邻三聚体之间，速率为32.51 ps。©2014 Wiley期刊公司。
Within the framework of the Förster theory, the electronic excitation energy transfer pathways in the cyanobacteria allophycocyanin (APC) trimer and hexamer were studied. The associated physical quantities (i.e., excitation energy, oscillator strength, and transition dipole moments) of the phycocyanobilins (PCBs) located in APC were calculated at time‐dependent density functional theory (TDDFT) level of theory. To estimate the influence of protein environment on the preceding calculated physical quantities, the long‐range interactions were approximately considered with the polarizable continuum model at the TDDFT level of theory, and the short‐range interaction caused by surrounding aspartate residue of PCBs were taken into account as well. The shortest energy transfer time calculated in the framework of the Förster model at TDDFT/B3LYP/6–31+G* level of theory are about 0.10 ps in the APC trimer and about 170 ps in the APC monomer, which are in qualitative agreement with the experimental finding that a very fast lifetime of 0.43–0.44 ps in APC trimers, whereas its monomers lacked any corresponding lifetime. These results suggest that the lifetime of 0.43–0.44 ps in the APC trimers determined by Sharkov et al. was most likely attributed to the energy transfer of α1‐84 ↔ β3‐84 (0.23 ps), β1‐84 ↔ α2‐84 (0.11 ps) or β2‐84 ↔ α3‐84 (0.10 ps). So far, no experimental or theoretical energy transfer rates between two APC trimmers were reported, our calculations predict that the predominate energy transfer pathway between APC trimers is likely to occur from α3‐84 in one trimer to α5‐84 in an adjacent trimer with a rate of 32.51 ps. © 2014 Wiley Periodicals, Inc.