Stuttgart 2012 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 11: Biomolecules
MO 11.1: Vortrag
Dienstag, 13. März 2012, 14:00–14:15, V38.02
The Sugar Ribose - Structural Complexity in the Gas Phase — E. J. Cocinero1, P. Écija1, F. Basterretxea1, J. A. Fernández1, F. Castaño1, A. Lesarri2, and •J.-U. Grabow3 — 1Universidad del País Vasco, Bilbao, Spain — 2Universidad de Valladolid, Valladolid, Spain — 3Gottfried-Wilhelm-Leibniz-Universität, Hannover, Germany
Sugars are cellular energy fuels, metabolic intermediates, mediators of cellular interactions and structural building blocks. Recently sugars moved into the focus of the quest for prebiotic building blocks in the interstellar medium as tracer for the construction of molecular complexity. However, sugars are structurally complex and elusive to experimental methods: the C5 D-aldose sugar, ribose, was only elucidated by X-ray crystal diffraction in 2010, but the structural information is biased by crystal packing forces. NMR methods conducted in condensed phases yield only solvent-averaged indirect structures.
In textbooks ribose is usually depicted as a β-furanose, predominant in ribonucleosides, ARN, ATP and other biochemically relevant derivatives. But is β-furanose the native form of free ribose? In order to solve these questions we conducted a rotational study of ribose combining FTMW spectroscopy in supersonic jets with ultrafast UV laser vaporization. We could detect six low-energy conformers, all belonging to the pyranose motif; in energetic order: cc-β-pyr 1C4, cc-β-pyr 4C1, c-β-pyr 1C4, c-α-pyr 1C4, cc-α-pyr 1C4, c-α-pyr 4C4. As given, the method also allows for unambiguous distinction between different orientations - clockwise/counterclockwise - of the hydroxyl groups.