Hannover 2013 – scientific programme

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MO: Fachverband Molekülphysik

MO 22: Biomolecules

MO 22.6: Talk

Thursday, March 21, 2013, 12:15–12:30, F 107

Metalated Hoogsteen binding in a nucleobase pair mimic by two-color IR dissociation spectroscopy — Yevgeniy Nosenko, Fabian Menges, Christoph Riehn, and •Gereon Niedner-Schatteburg — FB Chemie und Forschungszentrum OPTIMAS, TU Kaiserslautern, Erwin-Schrödinger-Str. 52, 67663 Kaiserslautern, Deutschland

Two Ag+ ions, deprotonated 1-methylthymine (1MT-H)- and 1,3-dideaza-adenine (DDA) self-assemble in methanolic solution to a cationic [(Ag)2(1MT-H)(DDA)]+ complex. This stoichiometry identifies in the course of electrospray ionization mass spectrometry. We compare one- and two-color IR Multiple Photon Dissociation spectra (1000-4000 cm-1) of trapped complexes with calculated DFT spectra in order to assign vibrational bands and to identify the silver coordination pattern. This approach reveals two structurally and energetically close isomers that resemble a metalated Hoogsteen-like binding motif invoking metallophilic interaction amongst the adjacent silver ions,[1] which has recently been postulated for a Hoogsteen-type double helix containing 18 contiguous Ag+ mediated base pairs between 1,3-dideaza-2'-deoxyadenosine and thymidine comprising two Ag+ ions per base pair.[2] A two color IR/IR double resonance scheme proved in particular useful to observe the weakly absorbing or weakly fragmenting vibrational bands.[1] References: [1] Y. Nosenko, F. Menges, C. Riehn and G. Niedner-Schatteburg, submitted to PCCP. [2] D. Megger, C. Guerra, J. Hoffmann, B. Brutschy, F. Bickelhaupt and J. Müller, Chemistry-a European Journal, 2011, 17, 6533