Initial characterization of the primary photochemistry of AppA, a blue-light-using flavin adenine dinucleotide-domain containing transcriptional antirepressor protein from Rhodobacter sphaeroides:: A key role for reversible intramolecular proton transfer from the flavin adenine dinucleotide chromophore to a conserved tyrosine?
Initial characterization of the primary photochemistry of AppA, a blue-light-using flavin adenine dinucleotide-domain containing transcriptional antirepressor protein from Rhodobacter sphaeroides:: A key role for reversible intramolecular proton transfer from the flavin adenine dinucleotide chromophore to a conserved tyrosine?
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DOI：
10.1562/0031-8655(2003)078
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发表时间：
2003-09-01
影响因子：
3.3
通讯作者：
Hellingwerf, KJ
中科院分区：
文献类型：
--
作者：
Laan, W;van der Horst, MA;Hellingwerf, KJ
来自紫色非硫细菌球形红杆菌的含有黄素腺嘌呤二核苷酸(FAD)的光感受器蛋白AppA(其中FAD与一个新的所谓的BLUF结构域结合)先前被证明是通过形成一个轻微红移的长寿命中间体而具有光活性的，该中间体被认为是信号状态。在这项研究中，我们使用UV-Vis和傅里叶变换红外光谱、pH测量和定点突变进一步表征了这种光感受器蛋白的初级光化学。现有证据表明，APPA的FAD发色团可能在受体状态下质子化，在信号状态下暴露于溶剂中。此外，实验数据表明，分子内质子转移(可能涉及[阴离子]Tyr-17)构成了信号态稳定的基础。
The flavin adenine dinucleotide (FAD)-containing photoreceptor protein AppA (in which the FAD is bound to a novel so-called BLUF domain) from the purple nonsulfur bacterium Rhodobacter sphaeroides was previously shown to be photoactive by the formation of a slightly redshifted long-lived intermediate that is thought to be the signaling state. In this study, we provide further characterization of the primary photochemistry of this photoreceptor protein using UV-Vis and Fourier-transform infrared spectroscopy, pH measurements and site-directed mutagenesis. Available evidence indicates that the FAD chromophore of AppA may be protonated in the receptor state, and that it becomes exposed to solvent in the signaling state. Furthermore, experimental data lead to the suggestion that intramolecular proton transfer (that may involve [anionic] Tyr-17) forms the basis for the stabilization of the signaling state.