Leids Instituut voor Chemisch Onderzoek, Universiteit Leiden, 2300 RA Leiden, The Netherlands.
Biochemistry. 2011 Dec 27;50(51):10987-9. doi: 10.1021/bi201504a. Epub 2011 Dec 1.
The red/far-red-sensing biological photoreceptor phytochrome is a paradigmatic two-state signaling system. The two thermally stable states are interconverted via a photoreaction of the covalently bound tetrapyrrole chromophore. Applying recently developed solid-state nuclear magnetic resonance, we study both the chromophore and its protein pocket in the Pr (red-absorbing) and Pfr (far-red-absorbing) states. The observations show that the phototransformation combines local chemical reactions with a mesoscopic transition of order. Both the chromophore and its binding pocket are quasi-liquid and disordered in Pr, yet quasi-solid and ordered in Pfr. Possible biochemical implications are discussed.
红光/远红光感光生物光受体光敏色素是一个典型的双态信号系统。两个热稳定状态通过共价结合的四吡咯发色团的光反应相互转换。应用最近开发的固态核磁共振技术，我们研究了发色团及其在 Pr（红光吸收）和 Pfr（远红光吸收）状态下的蛋白质口袋。观察结果表明，光转化将局部化学反应与介观有序转变相结合。在 Pr 中，发色团及其结合口袋都是准液体和无序的，而在 Pfr 中则是准固体和有序的。讨论了可能的生化意义。
