Protonated triplet-excited flavin resolved by step-scan FTIR spectroscopy: implications for photosensory LOV domains.
Protonated triplet-excited flavin resolved by step-scan FTIR spectroscopy: implications for photosensory LOV domains.
复制标题
通过步进扫描 FTIR 光谱解析质子化三线态激发黄素：对光感 LOV 域的影响。
DOI：
10.1039/c3cp43881c
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
T. Kottke
中科院分区：
文献类型：
--
作者：
Christian Thöing;Anna Pfeifer;S. Kakorin;T. Kottke
在许多其他功能中，黄素在蓝光传感器的LOV（光、氧或电压敏感）域中充当发色团。这些传感器调节许多生物体的中枢反应，例如植物对光的生长。黄素（（3）Fl）的三重激发态已被确定为LOV结构域光循环的关键中间体，无论是在其中性或质子化状态。即使时间分辨红外光谱也不能明确地分辨（3）Fl在光反应期间是否被质子化，因为质子化的三重激发态（3）FlH（+）以前没有被表征。本文采用步进扫描傅里叶变换红外光谱（step-scan Fourier transform infrared，FTIR）技术，研究了不同pH值下黄素单肽（flavin monoclastide，FMN）水溶液在1.5 μs ~ 860 μs范围内的激光诱导变化。建立了一个耐高压的流动池系统，以解释光反应的不可逆性和小的路径长度。在（3）Fl的水溶液光谱中识别出几个标记带，并通过量子化学计算进行了归属。这些谱带与（3）Fl在有机溶剂中的光谱相比，表现出溶剂诱导的位移。标记带在（3）FlH（+）形成后经历进一步明显的移位。带型可以清楚地从阴离子自由基或在电子供体存在下解析的完全还原状态的带型分离。与LOV结构域中的（3）Fl的光谱的比较得出以下结论：在这些蓝光传感器的光反应中没有形成（3）FlH（+）。
Among many other functions, flavin serves as a chromophore in LOV (light-, oxygen-, or voltage-sensitive) domains of blue light sensors. These sensors regulate central responses in many organisms such as the growth of plants towards light. The triplet-excited state of flavin ((3)Fl) has been identified as a key intermediate in the photocycle of LOV domains, either in its neutral or protonated state. Even time-resolved infrared spectroscopy could not resolve unambiguously whether (3)Fl becomes protonated during the photoreaction, because the protonated triplet-excited state (3)FlH(+) has not been characterized before. Here, the step-scan Fourier transform infrared (FTIR) technique was applied to the flavin mononucleotide (FMN) in aqueous solution at different pH values to resolve laser-induced changes in the time range from 1.5 μs to 860 μs. A high-pressure-resistant flow cell system was established to account for the irreversibility of the photoreaction and the small path length. Several marker bands were identified in the spectrum of (3)Fl in water and assigned by quantum chemical calculations. These bands exhibit a solvent-induced shift as compared with previous spectra of (3)Fl in organic solvents. The marker bands undergo a further distinct shift upon formation of (3)FlH(+). Band patterns can be clearly separated from those of the anion radical or the fully reduced state resolved in the presence of an electron donor. A comparison to spectra of (3)Fl in LOV domains leads to the conclusion that (3)FlH(+) is not formed in the photoreaction of these blue light sensors.
登录
查看更多内容
影响因子：
2.9
作者：
Halavaty, Andrei S.;Moffat, Keith
通讯作者：
Moffat, Keith
影响因子：
11.6
作者：
LISCUM, E;BRIGGS, WR
通讯作者：
BRIGGS, WR
向光素 LOV 域内光加合物形成和二级结构变化的时间分辨傅里叶变换红外研究
影响因子：
3.4
作者：
A. Pfeifer;T. Majerus;K. Zikihara;D. Matsuoka;S. Tokutomi;J. Heberle;T. Kottke
通讯作者：
T. Kottke
影响因子：
2.9
作者：
Kennis, JTM;Crosson, S;van Grondelle, R
通讯作者：
van Grondelle, R