Structure and mechanism of the photoactivatable green fluorescent protein.
Henderson, J.N., Gepshtein, R., Heenan, J.R., Kallio, K., Huppert, D., Remington, S.J.(2009) J Am Chem Soc 131: 4176-4177
- PubMed: 19278226 
- DOI: https://doi.org/10.1021/ja808851n
- Primary Citation of Related Structures:  
3GJ1, 3GJ2 - PubMed Abstract: 
Crystal structures of the photoactivatable green fluorescent protein T203H variant (PA-GFP) have been solved in the native and photoactivated states, which under 488 nm illumination are dark and brightly fluorescent, respectively. We demonstrate that photoactivation of PA-GFP is the result of a UV-induced decarboxylation of the Glu222 side chain that shifts the chromophore equilibrium to the anionic form. Coupled with the T203H mutation, which stabilizes the native PA-GFP neutral chromophore, Glu222 decarboxylation yields a 100-fold contrast enhancement relative to wild-type GFP (WT). Additionally, the structures provide insights into the spectroscopic differences between WT and PA-GFP steady-state fluorescence maxima and excited-state proton transfer dynamics.
Organizational Affiliation: 
Institute of Molecular Biology and Department of Physics, University of Oregon, Eugene, Oregon 97403-1229, USA.