|Title||The solution structure of a transient photoreceptor intermediate: Delta25 photoactive yellow protein.|
|Publication Type||Journal Article|
|Year of Publication||2005|
|Authors||Bernard, C., K. Houben, N. M. Derix, D. Marks, M. A. van der Horst, K. J. Hellingwerf, R. Boelens, R. Kaptein, and N. A. J. van Nuland|
|Date Published||2005 Jul|
|Keywords||Bacterial Proteins, Crystallography, X-Ray, Halorhodospira halophila, Light, Magnetic Resonance Spectroscopy, Models, Chemical, Models, Molecular, Models, Statistical, Photoreceptors, Microbial, Protein Conformation, Protein Folding, Protein Structure, Tertiary, Protons, Signal Transduction, X-Rays|
The N-terminally truncated variant of photoactive yellow protein (Delta25-PYP) undergoes a very similar photocycle as the corresponding wild-type protein (WT-PYP), although the lifetime of its light-illuminated (pB) state is much longer. This has allowed determination of the structure of both its dark- (pG) as well as its pB-state in solution by nuclear magnetic resonance (NMR) spectroscopy. The pG structure shows a well-defined fold, similar to WT-PYP and the X-ray structure of the pG state of Delta25-PYP. In the long-lived photocycle intermediate pB, the central beta sheet is still intact, as well as a small part of one alpha helix. The remainder of pB is unfolded and highly flexible, as evidenced by results from proton-deuterium exchange and NMR relaxation studies. Thus, the partially unfolded nature of the presumed signaling state of PYP in solution, as suggested previously, has now been structurally demonstrated.