IR-induced conformational isomerization of a helical peptide in a cold ion trap
| Autor: | Annette Svendsen, Caroline Seaiby, Aleksandra V. Zabuga, Thomas R. Rizzo |
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| Rok vydání: | 2016 |
| Předmět: |
Infrared Rays
Protein Conformation Population Analytical chemistry General Physics and Astronomy 02 engineering and technology 010402 general chemistry Mass spectrometry Photochemistry 01 natural sciences isomerization Ion cryogenic ion spectroscopy Physical and Theoretical Chemistry Spectroscopy education Conformational isomerism mass spectrometry Ions education.field_of_study Chemistry Stereoisomerism 021001 nanoscience & nanotechnology 0104 chemical sciences Excited state peptides Spectrophotometry Ultraviolet Ion trap 0210 nano-technology Isomerization |
| Zdroj: | The Journal of chemical physics |
| DOI: | 10.1063/1.4939528 |
| Popis: | In this work, we use laser-induced population transfer techniques to study the conformational isomerization of a helical peptide, Ac-Phe-(Ala)5-LysH(+), in a cold ion trap. In one scheme, called IR-UV hole-filling spectroscopy, a single conformation is selectively excited with an IR pump laser via a distinct NH stretch vibration. After giving the vibrationally excited ions sufficient time to isomerize and re-cool in the trap, the new conformational redistribution is detected by UV photofragment spectroscopy. While we clearly observe a redistribution of the conformer populations due to isomerization, only those conformations that initially have population participate in this redistribution-we do not form conformers that were not initially present in the trap. In a second scheme, called IR-induced population transfer spectroscopy, we determine the fractional populations of the four stable conformations of Ac-Phe-(Ala)5-LysH(+) by scanning the IR laser while selectively detecting a specific conformation using UV photofragment spectroscopy. |
| Databáze: | OpenAIRE |
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