Development and Characterization of Two Phenylalanine Derivatives for use as Raman Probes in Proteins

Abstract

Two promising Raman probe functional groups - terminal alkynes and aromatic nitro groups - were chosen to study the possibility of their ability to report on their molecular surroundings. These probes each have strong Raman signals and the potential to report on different physical aspects of their microscopic surroundings. To insert the probes into proteins, phenylalanine derivatives were synthesized with the probes added at the para-position. Extensive Raman solvatochromic experiments on model compounds containing the aromatic alkyne and nitro probes were used to determine the sensitivity of key vibrational mode frequencies to their environment. The two p-substituted phenylalanine derivatives were incorporated into interior positions of the e. coli fatty acid pathway's acyl carrier protein via unnatural amino acid incorporation techniques to better understand sequestration of substrates inside the pocket of the protein.