Highly dynamic motion of crown ethers along oligolysine peptide chains
Author: ["Dominik P. Weimann","Henrik D. F. Winkler","Jessica A. Falenski","Beate Koksch","Christoph A. Schalley"]
Publication: Nature Chemistry
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Abstract
Molecular mobility has attracted considerable attention in supramolecular chemistry and biochemistry, but the simple question of whether a small molecule can move directly between different binding sites of a multitopic host without intermediate dissociation has not been addressed so far. To study such processes, we consider hydrogen/deuterium exchange experiments on a model system comprising complexes formed between 18-crown-6 and oligolysine peptides. Because direct binding-site hopping is indistinguishable in solution from a dissociation/reassociation mechanism, here we show that the high vacuum of a mass spectrometer offers a unique environment for probing such processes. The highly dynamic motion of crown ethers along oligolysine peptide chains proceeds mechanistically by a simultaneous transfer of the crown ether from its ammonium ion binding site to a nearby amino group together with a proton. Furthermore, the exchange experiments unambiguously reveal the zwitterionic structure of the 18-crown-6/oligolysine complexes, highlighting the versatility and potential of gas-phase experiments for investigating non-covalent interactions. H/D exchange reactions in the high vacuum of a mass spectrometer reveal how crown ethers move between ammonium ion binding sites of an oligolysine peptide. This study enables the dynamics of non-covalent interactions to be probed in a unique environment and could be applied to more complex artificial or natural systems.
Cite this article
Weimann, D., Winkler, H., Falenski, J. et al. Highly dynamic motion of crown ethers along oligolysine peptide chains. Nature Chem 1, 573–577 (2009). https://doi.org/10.1038/nchem.352
