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Deciphering the Chemical Basis of Fluorescence of a Selenium‐Labeled Uracil Probe when Bound at the Bacterial Ribosomal A‐Site
Author(s) -
Cardenas Gustavo,
Menger Maximilian F. S. J.,
RamosBerdullas Nicolás,
SánchezMurcia Pedro A.
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202004818
Subject(s) - uracil , fluorophore , fluorescence , moiety , chemistry , photochemistry , stereochemistry , biochemistry , physics , dna , optics
We unveil in this work the main factors that govern the turn‐on/off fluorescence of a Se‐modified uracil probe at the ribosomal RNA A‐site. Whereas the constraint into an “in‐plane” conformation of the two rings of the fluorophore is the main driver for the observed turn‐on fluorescence emission in the presence of the antibiotic paromomycin, the electrostatics of the environment plays a minor role during the emission process. Our computational strategy clearly indicates that, in the absence of paromomycin, the probe prefers conformations that show a dark S 1 electronic state with participation of nπ* electronic transition contributions between the selenium atom and the π‐system of the uracil moiety.