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PDBsum entry 2pyp
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Photoreceptor
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PDB id
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2pyp
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References listed in PDB file
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Key reference
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Title
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Structure of a protein photocycle intermediate by millisecond time-Resolved crystallography.
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Authors
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U.K.Genick,
G.E.Borgstahl,
K.Ng,
Z.Ren,
C.Pradervand,
P.M.Burke,
V.Srajer,
T.Y.Teng,
W.Schildkamp,
D.E.Mcree,
K.Moffat,
E.D.Getzoff.
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Ref.
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Science, 1997,
275,
1471-1475.
[DOI no: ]
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PubMed id
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Abstract
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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.
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Figure 1.
Fig. 1. Chromophore structure (left) and difference
(|F[photostationary]| 
|F[dark]|) electron density map with PYP fold in the^ ground
state (white ribbon) and trans-chromophore (yellow) (right). The
density map (contoured at 3  ) shows an
excellent signal-to-noise^ ratio for the transient,
light-induced, structural changes. The^ largest signal is
localized at the active site (blue, positive; and red, negative
electron density). Figures 1 to 4 were made^ with AVS (28).
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Figure 4.
Fig. 4. Solvent-accessible molecular surface of PYP in (A)
the dark state and (C) bleached state color-coded for
electrostatic^ potential as calculated by DelPhi (29) (deep red,
< 4 kT;
white, neutral; dark blue, >4 kT). Partial charges were assigned
according to a revised version of the CHARMM force field (30).
In (B), C[  ]traces
and side chains of Arg52 for the dark (yellow) and bleached
(white) states are shown. Bleaching increases the positive
electrostatic potential at the^ active site. Movements of Arg52
and the chromophore change the surface shape.
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The above figures are
reprinted
by permission from the AAAs:
Science
(1997,
275,
1471-1475)
copyright 1997.
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