The solution structure of a transient photoreceptor intermediate: Delta25 photoactive yellow protein.
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.
Bernard
Cédric
C
Department of NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Houben
Klaartje
K
Derix
Nocky M
NM
Marks
David
D
van der Horst
Michael A
MA
Hellingwerf
Klaas J
KJ
Boelens
Rolf
R
Kaptein
Robert
R
van Nuland
Nico A J
NA
D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics*; D018360:Crystallography, X-Ray; D020607:Halorhodospira halophila / Q000378:metabolism; D008027:Light; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D015233:Models, Statistical; D020283:Photoreceptors, Microbial / Q000737:chemistry* / Q000235:genetics*; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011522:Protons; D015398:Signal Transduction; D014965:X-Rays
D001426:Bacterial Proteins; D020283:Photoreceptors, Microbial; D011522:Protons; C050162:photoactive yellow protein, Bacteria