New fluorescent probes for visual proteins Part I. Photophysical properties of 3-(oxo)propenyl-4′-(N,N-dimethylamino)benzoate

Abstract

Dual fluorescent compounds, derivatives of DMABN, are described which bear a spacer and an aldehyde group enabling their use as fluorescent probes in proteins containing amino functions. They are designed to be incorporated into the chromophore-binding pocket of the visual pigment rhodopsin or of the bacterial proton pump bacteriorhodopsin. The present study describes the synthesis and photophysical properties. The dual fluorescence observed is similar to that of the compound without attachment linker but the presence of several conformers and isomers brings in complications such as excitation wavelength dependence, spectral red shifts and low fluorescence quantum yields.