ROTATIONAL SPECTRA OF PHENYLALANINE, TIROSINE AND TRYPTOPHAN

Abstract

The rotational spectra of the aromatic natural amino acids phenylalanine, tyrosine and tryptophan have been investigated by Laser Ablation Molecular Beam Fourier transform Microwave Spectroscopy LA-MB-FTMW. The spectra of two rotamers of phenylalanine have been detected in the supersonic expansion. Both forms are stabilized by a chain of intramolecular hydrogen bonds O-H$\cdots$N-H$\cdots${$\pi$}, being the carboxylic group in\emph{cis} configuration. One conformer of tyrosine, which only differs from phenylalanine in a -OH group in\emph{para} position, has been also characterized. Preliminary results on the rotational spectrum of tryptophan are presented.