Raman and surface enhanced Raman spectroscopic studies of specific, small molecule activator of histone acetyltransferase p300

We report for the first time, the Raman and surface enhanced Raman scattering (SERS) studies of N-(4-chloro-3-trifluoromethyl-phenyl)-2-ethoxy-benzamide (CTB). This molecule is specific activator of human histone acetyltransferase (HAT), p300, and serves as lead molecule to design anti-neoplastic therapeutics. A detailed Raman and SERS band assignments have been performed for CTB, which are compared with the density functional theory calculations. The observed red shift of NH stretching frequency from the computed wavenumber indicates the weakening of NH bond resulting from proton transfer to the neighboring oxygen atom. We observe AgN vibrational mode at 234 cm−1 in SERS of CTB. This indicates there is a metal–molecule bond leading to chemical enhancement in SERS. We also observe, enhancement in the modes pertaining to substituted benzene rings and methyl groups. Based on SERS analysis we propose the adsorption sites and the orientation of CTB on silver surface.

► CTB is the only known specific activator for the human Histone Acetyl Transferase (HAT), p300.
► A detailed Raman and SERS band assignments have been performed and compared with DFT.
► A metal-molecule bond observed in SERS gives the chemical enhancement in SERS.
► We propose the adsorption sites and the orientation of CTB on Ag surface based on SERS analysis.