Real-Time Tracking of Phytochrome鈥檚 Orientational Changes During Pr Photoisomerization

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• 作者：Yang Yang ; Martin Linke ; Theodore von Haimberger ; Janina Hahn ; Ricardo Matute ; Leticia Gonz谩lez ; Peter Schmieder ; Karsten Heyne
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：January 25, 2012
• 年：2012
• 卷：134
• 期：3
• 页码：1408-1411
• 全文大小：272K
• 年卷期：v.134,no.3(January 25, 2012)
• ISSN：1520-5126

文摘

Photoisomerization of a protein bound chromophore is the basis of the light sensing and signaling responses of many photoreceptors. Z-to-E photoisomerization of the Pr Cph1螖2 phytochrome has been investigated by polarization resolved femtosecond visible pump-infrared probe spectroscopy, which yields structural information on the Pr excited (Pr*), Pr ground, and lumi-R product states. By exhaustive search analysis, two photoreaction time constants of (4.7 卤 1.4) and (30 卤 5) ps were found. Ring D orientational change in the electronic excited state to the transition state (90掳 twist) has been followed in real-time. Rotation of ring D takes place in the electronically excited state with a time constant of 30 卤 5 ps. The photoisomerization is best explained by a single rotation around C₁₅鈺怌₁₆ methine bridge in the Pr* state and a diffusive interaction with its protein surrounding.