Photoexcitation of the Blue Light Using FAD Photoreceptor AppA Results in Ultrafast Changes to the Protein Matrix
Photoexcitation of the Blue Light Using FAD Photoreceptor AppA Results in Ultrafast Changes to the Protein Matrix
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DOI：
10.1021/ja2060098
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发表时间：
2011-10-26
影响因子：
15
通讯作者：
Tonge, Peter J.
中科院分区：
文献类型：
--
作者：
Lukacs, Andras;Haigney, Allison;Tonge, Peter J.
BLUF光传感器AppA中黄素发色团的光激发导致构象变化，从而导致光传感器激活。这种构象变化是由围绕黄素的氢键网络介导的，并且已知光激发导致网络中的变化，包括与黄素C4=O羰基的氢键的加强。Q63是氢键网络中的关键残基，用谷氨酸取代该残基会产生光失活突变体。虽然Q63 E AppA（BLUF）的超快时间分辨红外（TRIR）光谱的特征在于1680和1650 cm（-1）处的黄素羰基模式，其频率与野生型蛋白质光激活状态的类似模式相似，在TRIR光谱中在1724 cm（-1）处也观察到一条带，基于蛋白质的U-C-13标记，该带明确地归属于Q63 E羧酸。光吸收瞬间（
Photoexcitation of the flavin chromophore in the BLUF photosensor AppA results in a conformational change that leads to photosensor activation. This conformational change is mediated by a hydrogen-bonding network that surrounds the flavin, and photoexcitation is known to result in changes in the network that include a strengthening of hydrogen bonding to the flavin C4=O carbonyl group. Q63 is a key residue in the hydrogen-bonding network, and replacement of this residue with a glutamate results in a photoinactive mutant. While the ultrafast time-resolved infrared (TRIR) spectrum of Q63E AppA(BLUF) is characterized by flavin carbonyl modes at 1680 and 1650 cm(-1), which are similar in frequency to the analogous modes from the light activated state of the wild-type protein, a band is also observed in the TRIR spectrum at 1724 cm(-1) that is unambiguously assigned to the Q63E carboxylic acid based on U-C-13 labeling of the protein. Light absorption instantaneously (