Heteronuclear NMR Investigation on the Structure and Dynamics of the Chromophore Binding Pocket of the Cyanobacterial Phytochrome Cph1.
- Resource Type
- Article
- Authors
- Hahn, Janina; Strauss, Holger M.; Schmieder, Peter
- Source
- Journal of the American Chemical Society. 8/20/2008, Vol. 130 Issue 33, p11170-11178. 9p. 6 Graphs.
- Subject
- *PHYTOCHROMES
*CYANOBACTERIA
*NUCLEAR magnetic resonance spectroscopy
*MOLECULAR structure
*MOLECULAR dynamics
*CONFORMATIONAL analysis
- Language
- ISSN
- 0002-7863
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 Cphl. On the basis of distance information obtained from three-dimensional nuclear Overhauser enhancement (3D-NOESY) spectra using the photochemically intact photosensory module of Cphl we demonstrate that the chromophore is in the ZZZssa form in the Pr (red absorbing form) state and the ZZEssa form in the Pfr (far-red absorbing form) state of the protein. While ZZZssa for the Pr state is in agreement with a recently determined X-ray structure, no comparable information for the Pfr state of photochemically intact phytochrome has been available up to now. In addition, the chromophore in the binding pocket of Cphl exhibits a notable mobility, which is distinctly different in the two photostates. [ABSTRACT FROM AUTHOR]