Absorption and emission spectroscopic characterization of BLUF protein Slr1694 from Synechocystis sp. PCC6803 with roseoflavin cofactor.
Absorption and emission spectroscopic characterization of BLUF protein Slr1694 from Synechocystis sp. PCC6803 with roseoflavin cofactor.
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DOI：
10.1016/j.jphotobiol.2009.08.002
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发表时间：
2009-11
期刊：
影响因子：
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通讯作者：
P. Zirak;A. Penzkofer;T. Mathes;P. Hegemann
中科院分区：
文献类型：
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作者：
P. Zirak;A. Penzkofer;T. Mathes;P. Hegemann
来自Synechocystis sp. PCC6803 （BLUF=blue-light sensor using FAD）的野生型BLUF蛋白Slr1694以黄素腺苷二核苷酸（FAD）为天然辅因子。这种光传感器引起海洋蓝藻的正趋光性。本研究将野生型Slr1694的FAD辅助因子替换为玫瑰黄素（RoF）和玫瑰黄素衍生物RoFMN和RoFAD，在核黄素营养不良大肠杆菌中进行异种表达。对辅助交换slr1694 （RoSlr）在黑暗和光照条件下的吸收和发射光谱进行了表征。在pH为8的水溶液中，比较了嵌入在RoSlr中的RoF在水溶液中的行为。室温下，RoF和RoSlr的荧光被光诱导的分子内扭曲电荷转移猝灭，RoF的猝灭作用更强，而在液氮温度下，荧光猝灭作用减弱。暴露在RoSlr光下，嵌入的玫瑰黄素蛋白不可逆地转化为8-甲氨基-黄素、8-二甲氨基-光色素和8-甲氨基-光色素。
The wild-type BLUF protein Slr1694 from Synechocystis sp. PCC6803 (BLUF=blue-light sensor using FAD) has flavin adenosine dinucleotide (FAD) as natural cofactor. This light sensor causes positive phototaxis of the marine cyanobacterium. In this study the FAD cofactor of the wild-type Slr1694 was replaced by roseoflavin (RoF) and the roseoflavin derivatives RoFMN and RoFAD during heterologous expression in a riboflavin auxotrophic E. coli strain. An absorption and emission spectroscopic characterization of the cofactor-exchanged-Slr1694 (RoSlr) was carried out both under dark conditions and under illuminated conditions. The behaviour of RoF embedded in RoSlr in aqueous solution at pH 8 is compared with the behaviour of RoF in aqueous solution. The fluorescence of RoF and RoSlr is quenched by photo-induced twisted intra-molecular charge transfer at room temperature with stronger effect for RoF. The fluorescence quenching is diminished at liquid nitrogen temperature. Light exposure of RoSlr causes irreversible conversion of the protein embedded roseoflavins to 8-methylamino-flavins, 8-dimethylamino-lumichrome and 8-methylamino-lumichrome.