2A50

fluorescent protein asFP595, wt, off-state

Summary for 2A50

• Entry DOI: 10.2210/pdb2a50/pdb
• Related: 2A52 2A53 2A54 2A56
• Descriptor: GFP-like non-fluorescent chromoprotein FP595 chain 1, GFP-like non-fluorescent chromoprotein FP595 chain 2 (3 entities in total)
• Functional Keywords: ascp, fluorescent protein, chromoprotein, photochromic protein, reversible photoswitch, luminescent protein
• Biological source: Anemonia sulcata (snake-locks sea anemone); More
• Total number of polymer chains: 4
• Total formula weight: 54449.82

Authors

Andresen, M.,Wahl, M.C.,Stiel, A.C.,Graeter, F.,Schaefer, L.,Trowitzsch, S.,Weber, G.,Eggeling, C.,Grubmueller, H.,Hell, S.W.,Jakobs, S. (deposition date: 2005-06-30, release date: 2005-08-16, Last modification date: 2011-07-13)

Primary citation

Andresen, M.,Wahl, M.C.,Stiel, A.C.,Graeter, F.,Schaefer, L.,Trowitzsch, S.,Weber, G.,Eggeling, C.,Grubmueller, H.,Hell, S.W.,Jakobs, S.
Structure and mechanism of the reversible photoswitch of a fluorescent protein
Proc.Natl.Acad.Sci.Usa, 102:13070-13074, 2005

PubMed Abstract: Proteins that can be reversibly photoswitched between a fluorescent and a nonfluorescent state bear enormous potential in diverse fields, such as data storage, in vivo protein tracking, and subdiffraction resolution light microscopy. However, these proteins could hitherto not live up to their full potential because the molecular switching mechanism is not resolved. Here, we clarify the molecular photoswitching mechanism of asFP595, a green fluorescent protein (GFP)-like protein that can be transferred from a nonfluorescent "off" to a fluorescent "on" state and back again, by green and blue light, respectively. To this end, we establish reversible photoswitching of fluorescence in whole protein crystals and show that the switching kinetics in the crystal is identical with that in solution. Subsequent x-ray analysis demonstrated that upon the absorption of a green photon, the chromophore isomerizes from a trans (off) to a cis (on) state. Molecular dynamics calculations suggest that isomerization occurs through a bottom hula twist mechanism with concomitant rotation of both bonds of the chromophoric methine ring bridge. This insight into the switching mechanism should facilitate the targeted design of photoswitchable proteins. Reversible photoswitching of the protein chromophore system within intact crystals also constitutes a step toward the use of fluorescent proteins in three-dimensional data recording.

PubMed: 16135569
DOI: 10.1073/pnas.0502772102

Experimental method

X-RAY DIFFRACTION (1.3 Å)