UV excited-state photoresponse of biochromophore negative ions.

Members of the green fluorescent protein (GFP) family may undergo irreversible phototransformation upon irradiation with UV light. This provides clear evidence for the importance of the higher-energy photophysics of the chromophore, which remains essentially unexplored. By using time-resolved action and photoelectron spectroscopy together with high-level electronic structure theory, we directly probe and identify higher electronically excited singlet states of the isolated para- and meta-chromophore anions of GFP.

Spectroscopic implications of the electron donor-acceptor effect in the photoactive yellow protein chromophore.

The importance of the donor-acceptor push-pull system in the photoabsorption of the trans p-coumaric acid, the cofactor within the photoactive yellow protein and other xanthopsins, has been investigated. We recorded gas-phase absorption spectra and performed high-level quantum chemical calculations of three chromophore models, namely, the deprotonated trans ortho-, meta- and para-methyl coumarates. The ortho and para isomers, which have the electron-donating phenoxy oxygen and the electron-withdrawing acyl group in conjugation, present absorptions in the high-energy region of the visible spectrum, that is, in the interval of wavelengths in which the photoactivity of the xanthopsins is observed.

On the absorption of the phenolate chromophore in the green fluorescent protein--role of individual interactions.

Model compounds of the green fluorescent protein (GFP) phenolate chromophore are synthesized and investigated for their intrinsic optical properties by state-of-the-art gas-phase action spectroscopy.

Gas phase absorption studies of photoactive yellow protein chromophore derivatives.

Photoabsorption spectra of deprotonated trans p-coumaric acid and two of its methyl substituted derivatives have been studied in gas phase both experimentally and theoretically. We have focused on the spectroscopic effect of the location of the two possible deprotonation sites on the trans p-coumaric acid which originate to either a phenoxide or a carboxylate. Surprisingly, the three chromophores were found to have the same absorption maximum at 430 nm, in spite of having different deprotonation positions.