Heidelberg 2015 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 18: Biomolecules
MO 18.3: Vortrag
Donnerstag, 26. März 2015, 11:45–12:00, PH/SR106
IRMPD spectra of metal-lumiflavin ionic complexes — •Alan Günther1, Pablo Nieto1, Giel Berden2, Jos Oomens2, Judith Langer1, and Otto Dopfer1 — 1Institut für Optik und Atomare Physik, TU Berlin, Berlin, Germany — 2Radboud University Nijmengen, Institute for Molecules and Materials FELIX Facility, Nijmengen , The Netherlands
Flavins are a fundamental class of biomolecules with lumiflavin (LF) as its smallest member. They are involved in many important biological processes. For example, as a component of flavo-proteins, they participate in the repair of DNA [1]. To understand these phenomena at the molecular level, spectroscopic studies of the geometric and electronic structure of isolated flavins and their complexes are required.We report IRMPD spectra of mass-selected Me+-LF (Me = Li, Na, K, Cs, Cu, Ag) ionic complexes in the fingerprint range (800-1900 cm−1) accompanied by DFT calculations. In solution, metal ions preferently bind to N5 and O4 of the flavin [2]. In contrast, additional O2 binding sites are identified for all alkali metal ions in our experiments, whereas for Cs+ only the O2 position is observed. For Ag+ and Cu+ only O4 and N5 chelates are identified, although the presence of the O2 isomer cannot be excluded. These metals also bind with different angles compared to alkali metals due to covalent contributions caused by their electronic configuration. The limited spectral resolution of these experiments will be overcome with our new apparatus equipped with a cryogenic 22-pole ion trap. [1] M.Sugiyama, EHP 92, 63 (1991); [2] P. Hemmerich and J. Lauterwein, Inorganic Biochemistry 1168 (1973)