Direct Measurement of the Isomerization Barrier of the Isolated Retinal Chromophore |
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| Authors: | Dr. Jonathan Dilger Lihi Musbat Prof. Mordechai Sheves Dr. Anastasia V. Bochenkova Prof. David E. Clemmer Dr. Yoni Toker |
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| Affiliation: | 1. Spectrum Warfare Systems Department, NSWC Crane Division, Crane, IN 47522 (USA);2. Institute of Nanotechnology and Advanced Materials, Bar‐Ilan University, Ramat‐Gan 290002 (Israel);3. Chemistry Department, Weizmann Institute of Science, Rehovot 978007 (Israel);4. Department of Physics and Astronomy, Aarhus University, DK‐8000 Aarhus C (Denmark);5. Department of Chemistry, Moscow State University, 119991 Moscow (Russia);6. Department of Chemistry, Indiana University, Bloomington, Indiana 47405 (USA) |
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| Abstract: | Isomerizations of the retinal chromophore were investigated using the IMS‐IMS technique. Four different structural features of the chromophore were observed, isolated, excited collisionally, and the resulting isomer and fragment distributions were measured. By establishing the threshold activation voltages for isomerization for each of the reaction pathways, and by measuring the threshold activation voltage for fragmentation, the relative energies of the isomers as well as the energy barriers for isomerization were determined. The energy barrier for a single cis–trans isomerization is (0.64±0.05) eV, which is significantly lower than that observed for the reaction within opsin proteins. |
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| Keywords: | chromophores gas‐phase reactions ion mobility spectroscopy isomerization proteins |
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