Ulrich K. Genick,
*
Gloria E. O. Borgstahl,
*
Kingman Ng,
§
Zhong Ren,
Claude Pradervand,
Patrick M. Burke,
Vukica 
rajer,
Tsu-Yi Teng,
Wilfried Schildkamp,
Duncan E. McRee,
Keith Moffat,
Elizabeth D. Getzoff
The blue-light photoreceptor photoactive yellow protein (PYP)
undergoes a self-contained light cycle. The atomic structure of the
bleached signaling intermediate in the light cycle of PYP was
determined by millisecond time-resolved, multiwavelength
Laue crystallography and simultaneous optical spectroscopy.
Light-induced trans-to-cis isomerization of the 4-hydroxycinnamyl
chromophore and coupled protein rearrangements produce a new set of
active-site hydrogen bonds. An arginine gateway opens, allowing solvent
exposure and protonation of the chromophore's phenolic oxygen.
Resulting changes in shape, hydrogen bonding, and electrostatic
potential at the protein surface form a likely basis for signal
transduction. The structural results suggest a general framework for
the interpretation of protein photocycles.
U. K. Genick, G. E. O. Borgstahl, P. M. Burke, D. E. McRee, E. D. Getzoff, Department of Molecular Biology, Scripps Research Institute,
10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
K. Ng, Z. Ren, C. Pradervand, V. rajer, T.-Y. Teng, W. Schildkamp, K. Moffat, Department of Biochemistry and Molecular
Biology, University of Chicago, 920 East 58th Street, Chicago, IL
60637, USA.
*
These authors contributed equally to this work.
These authors made major contributions to time-resolved
studies on photoactive yellow protein.
Present address: University of Toledo, Department of
Chemistry, Toledo, OH 43606, USA.
§
Present address: Eli Lilly and Company, Lilly Corporate
Center, Indianapolis, IN 46285, USA.
Present address: Department of Pathology, University of Utah
School of Medicine, Salt Lake City, UT 84132, USA.
