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Charge-induced unzipping of isolated proteins to a defined secondary structure

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González Flórez, A. I.; Mucha, E.; Ahn, D.-S.; Gewinner, S.; Schöllkopf, W.; Pagel, K.; von Helden, G.* – 2016

Here we present a combined experimental and theoretical study on the secondary structure of isolated proteins as a function of charge state. In infrared spectra of the proteins ubiquitin and cytochrome c, amide I (C=O stretch) and amide II (N–H bend) bands can be found at positions that are typical for condensed-phase proteins. For high charge states a new band appears, substantially red-shifted from the amide II band observed at lower charge states. The observations are interpreted in terms of Coulomb-driven transitions in secondary structures from mostly helical to extended C5-type hydrogen-bonded structures. Support for this interpretation comes from simple energy considerations as well as from quantum chemical calculations on model peptides. This transition in secondary structure is most likely universal for isolated proteins that occur in mass spectrometric experiments.

Title
Charge-induced Unzipping of Isolated Proteins to a Defined Secondary Structure
Author
González Flórez, A. I.; Mucha, E.; Ahn, D.-S.; Gewinner, S.; Schöllkopf, W.; Pagel, K.; von Helden, G.*
Date
2016
Identifier
10.1002/anie.201510983
Citation
Angew. Chem. Int. Ed. 2016, 55, 3295-3299
Type
Text
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