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Site‐Resolved Observation of Vibrational Energy Transfer Using a Genetically Encoded Ultrafast Heater
Author(s) -
Baumann Tobias,
Hauf Matthias,
Schildhauer Fabian,
Eberl Katharina B.,
Durkin Patrick M.,
Deniz Erhan,
Löffler Jan G.,
AcevedoRocha Carlos G.,
Jaric Jelena,
Martins Berta M.,
Dobbek Holger,
Bredenbeck Jens,
Budisa Nediljko
Publication year - 2019
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201812995
Subject(s) - allosteric regulation , picosecond , excitation , ultrashort pulse , förster resonance energy transfer , fluorescence , protein dynamics , chemistry , spectroscopy , alanine , energy transfer , amino acid , biophysics , protein structure , chemical physics , physics , biology , biochemistry , optics , laser , quantum mechanics , enzyme
Allosteric information transfer in proteins has been linked to distinct vibrational energy transfer (VET) pathways in a number of theoretical studies. Experimental evidence for such pathways, however, is sparse because site‐selective injection of vibrational energy into a protein, that is, localized heating, is required for their investigation. Here, we solved this problem by the site‐specific incorporation of the non‐canonical amino acid β‐(1‐azulenyl)‐ l ‐alanine (AzAla) through genetic code expansion. As an exception to Kasha's rule, AzAla undergoes ultrafast internal conversion and heating after S 1 excitation while upon S 2 excitation, it serves as a fluorescent label. We equipped PDZ3, a protein interaction domain of postsynaptic density protein 95, with this ultrafast heater at two distinct positions. We indeed observed VET from the incorporation sites in the protein to a bound peptide ligand on the picosecond timescale by ultrafast IR spectroscopy. This approach based on genetically encoded AzAla paves the way for detailed studies of VET and its role in a wide range of proteins.