Robustness of electronic coherence in the Fenna-Matthews-Olson complex to vibronic and structural modifications
Robustness of electronic coherence in the Fenna-Matthews-Olson complex to vibronic and structural modifications
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DOI：
10.1039/c0fd00030b
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发表时间：
2011-01-01
影响因子：
3.4
通讯作者：
Engel, Gregory S.
中科院分区：
文献类型：
--
作者：
Hayes, Dugan;Wen, Jianzhong;Engel, Gregory S.
我们提出的第一个二维电子光谱的光合天线复合物轴承修改的蛋白质和发色团。Fenna-Matthews-Olson复合物的电子振动结构被C-13几乎完全取代的天然丰富的碳和随机分布的部分氘分别改变。的细菌叶绿素a发色团的结构和安排进行了修改，通过删除的基因编码的酶负责减少类异戊二烯尾巴的细菌叶绿素。对应于激子1和2的串扰的时间依赖性振幅的分析表明，这些修改不影响在该特定峰中观察到的拍频的频率或失相。这一结果使我们得出结论，这种拍频确实来自电子相干性，而不是振动波包运动。我们进一步得出结论，这种光合作用复合物的蛋白质基质所提供的零量子相干性的保护不是经过数十亿年进化完善的一系列微调系统浴相互作用的结果，而是声子浴内紧密排列的发色团的简单下游性质。最后，我们简要讨论了这一现象的悬而未决的问题和可能的应用。
We present the first two-dimensional electronic spectra of photosynthetic antenna complexes bearing modifications to the protein and the chromophores. The vibronic structure of the Fenna-Matthews-Olson complex was altered by near-complete substitution of C-13 for naturally abundant carbon and separately by randomly distributed partial deuteration. The structure and arrangement of the bacteriochlorophyll a chromophores were modified by deletion of the gene encoding the enzyme responsible for reducing the isoprenoid tail of the bacteriochlorophylls. Analysis of the time-dependent amplitude of the crosspeak corresponding to excitons 1 and 2 indicates that these modifications do not affect the frequency or dephasing of the beating observed in this particular peak. This result leads us to conclude that this beating indeed arises from electronic coherence and not vibrational wavepacket motion. We further conclude that the protection of zero-quantum coherences afforded by the protein matrix of this photosynthetic complex is not the result of a finely-tuned series of system-bath interactions perfected by billions of years of evolution but rather a simple downstream property of a close arrangement of chromophores within a phonon bath. We conclude with a brief discussion of the outstanding questions and possible applications of this phenomenon.