Transient dimerization and conformational change of a BLUF protein: YcgF
Transient dimerization and conformational change of a BLUF protein: YcgF
复制标题
DOI：
10.1021/ja065682q
复制
发表时间：
2007-06-06
影响因子：
15
通讯作者：
Terazima, Masahide
中科院分区：
文献类型：
--
作者：
Nakasone, Yusuke;Ono, Taka-aki;Terazima, Masahide
利用脉冲激光诱导瞬态光栅（TG）技术研究了BLUF蛋白质YcgF的光化学反应动力学。TG信号显示三个反应时间常数：2.7 μ s，13 μ s，和2毫秒。最快的是暂时归因于放松的激发三重态的发色团，黄素腺嘌呤二核苷酸（FAD），和其他代表的蛋白质的构象变化。TG信号提供了明确的证据，证明光产物的扩散系数（D）（3.8 × 10（-11）m（2）s（-1））明显小于反应物的扩散系数（8.3 × 10（-11）m（2）s（-1）），在700 μ M的蛋白质浓度下，时间常数为2 ms。有趣的是，速率常数的增加成比例的蛋白质的浓度，表明蛋白质二聚化的主要反应发生后，光激发。D的显著降低表明在形成信号传导状态时发生导致与水分子的相互作用增加的构象变化。13亩的动力学归因于诱导瞬时二聚化的构象变化。这种构象变化可能是产生信号状态的一个重要过程。提出了YcgF光化学反应的详细方案。
The photochemical reaction dynamics of YcgF, a BLUF protein, were investigated by the pulsed laser-induced transient grating (TG) technique. The TG signal showed three reaction time constants: 2.7 mu s, 13 mu s, and 2 ms. The fastest was tentatively attributed to relaxation of the excited triplet state of the chromophore, flavin adenine dinucleotide (FAD), and the others represented conformational changes of the protein. The TG signal provided clear evidence that the diffusion coefficient (D) of the photoproduct (3.8 x 10(-11) m(2) s(-1)) was significantly less than that of the reactant (8.3 x 10(-11) m(2) s(-1)), with a time constant of 2 ms at a protein concentration of 700 mu M. Interestingly, the rate constant increased in proportion to the concentration of the protein, indicating that protein dimerization was one of the main reactions occurring after photoexcitation. The significant reduction in D indicates that a conformational change leading to an increase in interactions with water molecules occurs upon formation of the signaling state. The 13 mu s dynamics was attributed to the conformational change that induced transient dimerization. This conformational change might be an essential process for the creation of the signaling state. A detailed scheme for the photochemical reaction of YcgF is proposed.