Dronpa

Dronpa is a reversibly switchable photoactivatable fluorescent protein that is 2.5 times as bright as EGFP.

A tetrameric,[4] reversibly switchable fluorescent protein was discovered in a cDNA screen of a stony coral (Pectiniidae).

A monomeric variant of this protein was named "Dronpa" after "Dron" a ninja term for vanishing and pa for photoactivation.

Several other residues in the vicinity of the chromophore also move during the on-off transition resulting a very different electrostatic environment.

[5] Dronpa's fast dynamics and stability under repeated cycles of switching make it one of the more important switchable fluorescent proteins.

An animation of the structure of the dark state of dronpa protein
On-cis (green) and Off-trans (yellow) states of the chromophore. Nearby residues that move are also shown. Clockwise from the top: Arg66, Val157, Ser142, Cys-Tyr-Gly chromophore.