Time-resolved fluctuation during the photochemical reaction of a photoreceptor protein: phototropin1LOV2-linker.
Time-resolved fluctuation during the photochemical reaction of a photoreceptor protein: phototropin1LOV2-linker.
复制标题
光感受器蛋白光化学反应过程中的时间分辨波动：phototropin1LOV2-linker。
DOI：
10.1039/c5cp07472j
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Terazima M.
中科院分区：
文献类型：
--
作者：
Kuroi K;Sato F;Nakasone Y;Zikihara K;Tokutomi S;Terazima M.
虽然结构波动与反应之间的关系对阐明反应机理很重要，但描述这种反应中间体波动的实验数据很少。为了研究蛋白质反应过程中的结构波动，利用高压光学电池的瞬态光栅和瞬态透镜方法，测量了具有J-α螺旋的典型LOV结构域c端连接子phot1lov2连接子光激发后中间物质的可压缩性。相对于0.1 MPa时，生色团与Cys残基形成共价键（S态形成）的产率随着压力的增加而略有下降。在压力（0.1-200 MPa）范围内，产生T态（连接物未折叠态）的反应物质的比例几乎成比例地下降到65%左右。有趣的是，与反应相关的体积变化对压力更敏感。通过结合这些数据，确定了短寿命中间产物（S态）和最终产物（T态）形成的可压缩性变化。与暗(D)态相比，S态的可压缩性增加，而从S态过渡到T态时可压缩性降低。从蛋白质内部空腔的角度讨论了可压缩性的变化。通过比较phot1lov2 -链接器在暗态和亮态下的晶体结构，我们得出结论，在S态下，LOV域和链接器域之间的空腔体积增加，这解释了可压缩性的增强。
Although the relationship between structural fluctuations and reactions is important for elucidating reaction mechanisms, experimental data describing such fluctuations of reaction intermediates are sparse. In order to investigate structural fluctuations during a protein reaction, the compressibilities of intermediate species after photoexcitation of a phot1LOV2-linker, which is a typical LOV domain protein with the C-terminal linker including the J-α helix and used recently for optogenetics, were measured in the time-domain by the transient grating and transient lens methods with a high pressure optical cell. The yield of covalent bond formation between the chromophore and a Cys residue (S state formation) relative to that at 0.1 MPa decreased very slightly with increasing pressure. The fraction of the reactive species that yields the T state (linker-unfolded state) decreased almost proportionally with pressure (0.1–200 MPa) to about 65%. Interestingly, the volume change associated with the reaction was much more pressure sensitive. By combining these data, the compressibility changes for the short lived intermediate (S state) and the final product (T state) formation were determined. The compressibility of the S state was found to increase compared with the dark (D) state, and the compressibility decreased during the transition from the S state to the T state. The compressibility change is discussed in terms of cavities inside the protein. By comparing the crystal structures of the phot1LOV2-linker at dark and light states, we concluded that the cavity volumes between the LOV domain and the linker domain increase in the S state, which explains the enhanced compressibility.