1W7T

Photoproduct of the Wild-Type Aequorea victoria Green Fluorescent Protein at 100 K

Summary for 1W7T

• Entry DOI: 10.2210/pdb1w7t/pdb
• Related: 1B9C 1BFP 1C4F 1CV7 1EMA 1EMB 1EMC 1EME 1EMF 1EMG 1EMK 1EML 1EMM 1F09 1F0B 1GFL 1H6R 1HCJ 1HUY 1JBY 1JBZ 1JC0 1JC1 1KP5 1KYP 1KYR 1KYS 1MYW 1Q4A 1Q4B 1Q4C 1Q4D 1Q4E 1Q73 1QXT 1QY3 1QYF 1QYO 1QYQ 1RM9 1RMM 1RMO 1RMP 1RRX 1W7S 1W7U 1YFP 2EMD 2EMN 2EMO
• Descriptor: GREEN FLUORESCENT PROTEIN (2 entities in total)
• Functional Keywords: luminescent protein, beta-barrel, bioluminescence, photoproduct
• Biological source: AEQUOREA VICTORIA
• Total number of polymer chains: 4
• Total formula weight: 107549.38

Authors

Van Thor, J.J.,Georgiev, G.Y.,Towrie, M.,Sage, J.T. (deposition date: 2004-09-09, release date: 2005-07-20, Last modification date: 2023-12-13)

Primary citation

Van Thor, J.J.,Georgiev, G.Y.,Towrie, M.,Sage, J.T.
Ultrafast and Low Barrier Motions in the Photoreactions of the Green Fluorescent Protein
J.Biol.Chem., 280:33652-, 2005

PubMed Abstract: Green fluorescent protein (GFP) fluoresces efficiently under blue excitation despite major electrostatic rearrangements resulting from photoionization of the chromophore and neutralization of Glu-222. A competing phototransformation process, which ionizes the chromophore and decarboxylates Glu-222, mimics the electrostatic and structural changes in the fluorescence photocycle. Structural and spectroscopic analysis of the cryogenically stabilized photoproduct at 100 K and a structurally annealed intermediate of the phototransformed protein at 170 K reveals distinct structural relaxations involving protein, chromophore, solvent, and photogenerated CO2. Strong structural changes of the 100 K photoproduct after decarboxylation appear exclusively within 15 angstroms of the chromophore and include the electrostatically driven perturbations of Gln-69, Cys-70, and water molecules in an H-bonding network connecting the chromophore. X-ray crystallography to 1.85 angstroms resolution and static and picosecond time-resolved IR spectroscopy identify structural mechanisms common to phototransformation and to the fluorescence photocycle. In particular, the appearance of a 1697 cm(-1) (+) difference band in both photocycle and phototransformation intermediates is a spectroscopic signature for the structural perturbation of Gln-69. This is taken as evidence for an electrostatically driven dynamic response that is common to both photoreaction pathways. The interactions between the chromophore and the perturbed residues and solvent are decreased or removed in the T203H single and T203H/Q69L double mutants, resulting in a strong reduction of the fluorescence quantum yield. This suggests that the electrostatic response to the transient formation of a buried charge in the wild type is important for the bright fluorescence.

PubMed: 16033764
DOI: 10.1074/JBC.M505473200

Experimental method

X-RAY DIFFRACTION (1.85 Å)