Heteronuclear NMR Investigation on the Structure and Dynamics of the Chromophore Binding Pocket of the Cyanobacterial Phytochrome Cph1

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• 作者：Janina Hahn ; Holger M. Strauss ; Peter Schmieder
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：August 20, 2008
• 年：2008
• 卷：130
• 期：33
• 页码：11170-11178
• 全文大小：322K
• 年卷期：v.130,no.33(August 20, 2008)
• ISSN：1520-5126

文摘

Structural changes of the chromophore in phytochrome proteins associated with its photocycle are still not fully understood. We use heteronuclear NMR to investigate the conformation and dynamics of the chromophore in the binding pocket of the cyanobacterial phytochrome Cph1. On the basis of distance information obtained from three-dimensional nuclear Overhauser enhancement (3D-NOESY) spectra using the photochemically intact photosensory module of Cph1 we demonstrate that the chromophore is in the ZZZssa form in the P_r (red absorbing form) state and the ZZEssa form in the P_fr (far-red absorbing form) state of the protein. While ZZZssa for the P_r state is in agreement with a recently determined X-ray structure, no comparable information for the P_fr state of photochemically intact phytochrome has been available up to now. In addition, the chromophore in the binding pocket of Cph1 exhibits a notable mobility, which is distinctly different in the two photostates.