title: Isolated β-turn model systems investigated by combined IR/UV spectroscopy.
abstract: The functionality of bioactive molecules sensitively depends on their structure. For the investigation of intrinsic structural properties, molecular beam experiments combined with laser spectroscopy have proven to be a suitable tool. Herein we present an analysis of the two isolated tripeptide model systems Ac-Phe-Tyr(Me)-NHMe and Boc-Phe-Tyr(Me)-NHMe. For this purpose, mass-selective combined IR/UV spectroscopy is applied to both substances in a molecular beam experiment. The comparison of the experimental data with DFT calculations, including different functionals as well as dispersion corrections, allows an assignment of both tripeptide models to β-turns formed independently from the protection groups and supported by the interaction of the two aromatic chromophores.
authors.affiliation: Fachbereich Chemie and research center OPTIMAS, Physikalische und Theoretische Chemie, TU Kaiserslautern, Kaiserslautern, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Schwing
authors.forename: Holger
authors.initials: H
authors.lastname: Fricke
authors.forename: Kristina
authors.initials: K
authors.lastname: Bartl
authors.forename: Jolanta
authors.initials: J
authors.lastname: Polkowska
authors.forename: Thomas
authors.initials: T
authors.lastname: Schrader
authors.forename: Markus
authors.initials: M
authors.lastname: Gerhards
mesh_terms: D007536:Isomerism; D008958:Models, Molecular; D017433:Protein Structure, Secondary; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet