Hannover 2016 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 9: Biomolecules and Photochemistry

MO 9.1: Hauptvortrag

Dienstag, 1. März 2016, 14:30–15:00, f102

Structural investigations on a linear depsipeptide and cyclopeptides by combined IR/UV spectroscopy: Importance of dispersion interactions — Anke Stamm, Dominic Bernhard, and •Markus Gerhards — TU Kaiserslautern, Fachbereich Chemie, Erwin-Schrödinger-Str. 52, 67663 Kaiserslautern

Depsipeptides as a special subclass of peptides contain at least one ester bond replacing a peptide bond which gives rise to a different folding behavior compared to an ordinary peptide. For a better understanding of their biological activity on a molecular level, knowledge on the structure of the isolated depsipeptides is of importance. As a first model system investigated in a molecular beam experiment we have chosen cyclohexylcarbonyl-glycine-lactate-2-anisidine (CyCO-Gly-Lac-NH-PhOMe; abbrev.MOC). MOC represents a linear depsipeptide whose structural investigation should give basic insights into preferred conformations of isolated depsipeptides. The system contains both an aromatic phenyl ring and an aliphatic cyclohexyl ring which interact via CH/π dispersion interactions. This structure is only stable if dispersion is taken into account. An experimental analysis on the depsipeptide as well as on cyclopeptides is performed by application of mass- and isomer-selective combined double and triple resonance IR/UV methods in a molecular beam. In order to assign structures, DFT calculations including dispersion corrections were performed and compared with the experimental IR spectra.