Photoreaction of the cysteine S-H group in the LOV2 domain of adiantum phytochrome3
Photoreaction of the cysteine S-H group in the LOV2 domain of adiantum phytochrome3
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DOI：
10.1021/ja020834c
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发表时间：
2002-10-09
影响因子：
15
通讯作者：
Kandori, H
中科院分区：
文献类型：
--
作者：
Iwata, T;Tokutomi, S;Kandori, H
PHY3-LOV2是植物趋向性反应的蓝光感光器的生色团结构域。FMN与PHY3-LOV2非共价结合，其蛋白质结构具有光氧压(LOV)结构域的特征。主要的光反应被认为是FMN与半胱氨酸形成加合物，而半胱氨酸S−H基团被认为是去质子化。红外光谱分析表明，PHA3-LOV2的半胱氨酸是质子化的S−H形式，而不是基态的硫代形式。在S390形成后，S的−H基团消失，可能形成了FmN和Cys966之间的加合物。S390在150K可以被捕获，而在295K时，S390的蛋白质结构可能不会发生显著变化。
Phy3-LOV2 is the chromophore domain of a blue-light photoreceptor for tropic responses of plants. FMN is noncovalently bound to phy3-LOV2, and the protein structure is characteristic of the LOV (light-oxygen-voltage) domain. Primary photoreaction is considered to be adduct formation between FMN and a cysteine, while deprotonation of the cysteine S−H group was suggested. On the basis of the infrared spectral analysis, however, we have shown that the cysteine of phy3-LOV2 is in the protonated S−H form, and not in the thiolate form in the ground state. Upon formation of S390, the S−H group disappears, presumably forming the adduct between FMN and Cys966. S390 can be trapped at 150 K, and the protein structure of S390 may not be changed drastically at 295 K.