Spectral Signatures of Canthaxanthin Translocation in the Orange Carotenoid Protein
Spectral Signatures of Canthaxanthin Translocation in the Orange Carotenoid Protein
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DOI：
10.1021/acs.jpcb.0c08756
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发表时间：
2020-12-17
影响因子：
3.3
通讯作者：
Gascon, Jose A.
中科院分区：
文献类型：
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作者：
Pigni, Natalia B.;Clark, Kevin L.;Gascon, Jose A.
橙子类胡萝卜素蛋白（OCP）通过非光化学猝灭参与蓝藻的光保护过程。由蓝绿光吸收触发，类胡萝卜素发色团经历易位，从C-末端结构域（CTD）到N-末端结构域（NTD）置换约12 A。在这个过程中，类胡萝卜素和蛋白质内部发生的详细分子重排在很大程度上仍然难以捉摸。通过使用分子动力学的组合，良好的回火metadaptics，和混合量子力学/分子力学（QM/MM）的计算，我们能够模拟类胡萝卜素的易位从非活性OCPO和获得亚稳态的红移状态的光活化机制，复制的λ（最大）值的参考实验光谱。此外，我们的模拟给洞察的结构的红移形式的非活性状态的OCP。
The orange carotenoid protein (OCP) is involved in the photoprotective processes in cyanobacteria via nonphotochemical quenching. Triggered by blue-green light absorption, the carotenoid chromophore undergoes translocation, displacing around 12 A from the C-terminal domain (CTD) to the N-terminal domain (NTD). The detailed molecular rearrangements that occur within the carotenoid and the protein during this process remain largely elusive. By using a combination of molecular dynamics, well-tempered metadynamics, and hybrid quantum mechanical/molecular mechanical (QM/MM) calculations, we were able to mimic the translocation of the carotenoid from the inactive OCPO and obtain metastable red-shifted states in the photoactivation mechanism, replicating the lambda(max) values of reference experimental spectra. In addition, our simulations give insight into the structure of the red-shifted form of the inactive state of OCP.