Surface-enhanced Raman scattering and fluorescence spectroscopy reveal molecular interactions of all-trans retinoic acid and RARγ ligand-binding domain

Surface-enhanced Raman scattering and fluorescence were used to investigate the interactions of all-trans retinoic acid with the gamma-type retinoic acid receptor. Raman data revealed a significant attenuation in intensity of the bands originating from the retinoic acid polyenic chain upon receptor binding, with the spectrum being dominantly that of the β-ionone ring. Fluorescence measurements supported the hydrophobic character of the ligand binding. These novel spectroscopic results are fully consistent with the published X-ray crystallographic data and suggest that these techniques may be valuable additional tools to characterize the interactions of agonists and antagonists with residues in the ligand-binding pockets of retinoid receptor homo- and heterodimers. © 1998 John Wiley & Sons, Inc. Biospectroscopy 4: 297–302, 1998