title: Matrix-isolation FT-IR spectroscopic study and theoretical DFT(B3LYP)/6-31++G** calculations of the vibrational and conformational properties of tyrosine.
abstract: The complicated conformational isomerism of tyrosine is studied by experimental matrix-isolation FT-IR spectroscopy combined with theoretical DFT(B3LYP)/6-31++G** calculations. Not less than 18 possible conformations of tyrosine have been considered theoretically. The results revealed that the most and the less stable forms of neutral tyrosine have the same conformation of the main part of amino acid (conformation II) but they differ in orientation of the phenyl ring. The calculated values of the relative energies suggest that all conformations would be detectable in the experimental spectrum. However, it appeared that it is not possible to distinguish in the experimental spectrum between the bands due to the forms with the same conformation of the main part of amino acid but a different orientation of the phenol ring.
authors.affiliation: Department of Chemistry, University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
authors.forename: Riet
authors.initials: R
authors.lastname: Ramaekers
authors.forename: Joanna
authors.initials: J
authors.lastname: Pajak
authors.forename: Maria
authors.initials: M
authors.lastname: Rospenk
authors.forename: Guido
authors.initials: G
authors.lastname: Maes
mesh_terms: D008962:Models, Theoretical; D008968:Molecular Conformation; D019800:Phenol / Q000737:chemistry; D013053:Spectrophotometry / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013816:Thermodynamics; D014443:Tyrosine / Q000737:chemistry*
chemical_list: D019800:Phenol; D014443:Tyrosine