2PYR: Photoactive Yellow Protein, 1 Nanosecond Intermediate (287k)

Photoactive yellow protein (PYP) is a member of the xanthopsin family of eubacterial blue-light photoreceptors. On absorption of light, PYP enters a photocycle that ultimately transduces the energy contained in a light signal into an altered biological response. Nanosecond time-resolved x-ray crystallography was used to determine the structure of the short-lived, red-shifted, intermediate state denoted [pR], which develops within 1 nanosecond after photoelectronic excitation of the chromophore of PYP by absorption of light. The resulting structural model demonstrates that the [pR] state possesses the cis conformation of the 4-hydroxyl cinnamic thioester chromophore, and that the process of trans to cis isomerization is accompanied by the specific formation of new hydrogen bonds that replace those broken upon excitation of the chromophore. Regions of flexibility that compose the chromophore-binding pocket serve to lower the activation energy barrier between the dark state, denoted pG, and [pR], and help initiate entrance into the photocycle. Direct structural evidence is provided for the initial processes of transduction of light energy, which ultimately translate into a physiological signal.
PDB ID: 2PYRDownload
MMDB ID: 58176
PDB Deposition Date: 1998/3/4
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 1.9  Å
Source Organism:
Similar Structures:
Biological Unit for 2PYR: monomeric; determined by author
Molecular Components in 2PYR
Label Count Molecule
Protein (1 molecule)
Photoactive Yellow Protein
Molecule annotation
Chemical (1 molecule)
* Click molecule labels to explore molecular sequence information.

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