Time-resolved Fourier transform infrared study on photoadduct formation and secondary structural changes within the phototropin LOV domain.
Time-resolved Fourier transform infrared study on photoadduct formation and secondary structural changes within the phototropin LOV domain.
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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
DOI：
10.1016/j.bpj.2008.11.016
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发表时间：
2009
影响因子：
3.4
通讯作者：
T. Kottke
中科院分区：
文献类型：
--
作者：
A. Pfeifer;T. Majerus;K. Zikihara;D. Matsuoka;S. Tokutomi;J. Heberle;T. Kottke
趋光蛋白是植物蓝光光感受器，含有两个光、氧或电压敏感（LOV）结构域和一个C-末端激酶结构域。两个LOV结构域非共价结合黄素单核苷酸作为发色团。采用分步扫描傅里叶变换红外光谱法研究了假单胞菌光敏素2的快速恢复突变株LOV 2-I403 V的光循环特性。黄素的三重激发态与半胱氨酸发生反应，时间常数为3μs，生成共价加合物。我们的数据提供的证据表明，黄素是非质子化的生产三重态，不利于键形成的离子机制。一个中间加合物物种是明显的，显示在螺旋或环区域的二级结构的变化，并以120μs的时间常数松弛。在毫秒内，最终的加合物状态通过二级结构的进一步改变（包括β-折叠）形成。与野生型加合物光谱的比较表明，突变不干扰域的功能。所有信号都源自LOV结构域内，因为构建体不包含信号转导所需的相邻Jα螺旋。讨论了早期和晚期加合物中间体对信号传递到结构域外的Jα螺旋的贡献。
Phototropins are plant blue-light photoreceptors containing two light-, oxygen-, or voltage-sensitive (LOV) domains and a C-terminal kinase domain. The two LOV domains bind noncovalently flavin mononucleotide as a chromophore. We investigated the photocycle of fast-recovery mutant LOV2-I403V fromArabidopsisphototropin 2 by step-scan Fourier transform infrared spectroscopy. The reaction of the triplet excited state of flavin with cysteine takes place with a time constant of 3μs to yield the covalent adduct. Our data provide evidence that the flavin is unprotonated in the productive triplet state, disfavoring an ionic mechanism of bond formation. An intermediate adduct species was evident that displayed changes in secondary structure in the helix or loop region, and relaxed with a time constant of 120μs. In milliseconds, the final adduct state is formed by further alterations of secondary structure, includingβ-sheets. A comparison with wild-type adduct spectra shows that the mutation does not interfere with the functionality of the domain. All signals originate from within the LOV domain, because the construct does not comprise the adjacent Jαhelix required for signal transduction. The contribution of early and late adduct intermediates to signal transfer to the Jαhelix outside of the domain is discussed.
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影响因子：
2.9
作者：
Imamoto, Y;Kataoka, M;Tokunaga, F
通讯作者：
Tokunaga, F
影响因子：
3.1
作者：
Bednarz, T;Losi, A;Heberle, J
通讯作者：
Heberle, J
影响因子：
15
作者：
Sato, Y;Iwata, T;Kandori, H
通讯作者：
Kandori, H
影响因子：
2.9
作者：
Crosson, S;Rajagopal, S;Moffat, K
通讯作者：
Moffat, K
向光素 C450A 突变体中光诱导中性黄素自由基的检测和表征*
DOI：
--
发表时间：
2003
期刊：
影响因子：
--
作者：
C. W. Kay;E. Schleicher;Andreas Kuppig;H. Hofner;M. Schleicher;M. Fischer;A. Bacher;S. Weber;G. Richter
通讯作者：
G. Richter