Synthetic green fluorescent protein chromophore analogues with a positive charge at the phenyl-like group

Abstract

Synthetic green fluorescent protein (GFP) chromophore analogues with a positive charge at the phenyl-like group have the highly electrophilic amidine carbon, smaller LUMO-HOMO energy gap, red-shifted electronic absorptions and fluorescent emissions, and accelerated E-Z thermoisomerization rates. They are water-labile and their hydrolysis results in ring-opening of the imidazolinone moiety with a half life around 25-37 h in D₂O at 25 °C.

Keywords: Green fluorescent protein; Photophysical properties; Reactivity.