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pH‐Dependent Absorption Spectrum of Oxyluciferin Analogues in the Presence of Adenosine Monophosphate
Author(s) -
Manuel de Almeida Barbosa Nuno,
Zemmouche Madjid,
Gosset Pauline,
GarcíaIriepa Cristina,
Ledentu Vincent,
Navizet Isabelle,
Didier Pascal,
Ferré Nicolas
Publication year - 2019
Publication title -
chemphotochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.13
H-Index - 18
ISSN - 2367-0932
DOI - 10.1002/cptc.201900150
Subject(s) - chemistry , protonation , qm/mm , absorption (acoustics) , absorption spectroscopy , molecular dynamics , adenosine monophosphate , proton , spectroscopy , photochemistry , computational chemistry , adenosine , materials science , organic chemistry , physics , quantum mechanics , ion , biochemistry , composite material
The photophysical properties of oxyluciferin, the light emitter responsible for firefly bioluminescence, are pH‐dependent. One of the potential proton acceptor/donor is adenosine monophosphate (AMP). We have studied three oxyluciferin synthetic analogues with or without AMP, in water, in the pH=5 to 11 range, using both experimental steady‐state absorption spectroscopy or the recently developed computational protocol that uses constant pH molecular dynamics and then hybrid QM/MM calculations (CpHMD‐then‐QM/MM). The latter features a systematic investigation of all the protonation microstates using molecular dynamics simulations coupled to thousands hybrid QM/MM vertical excitation energies. Our results demonstrate that AMP does not significantly modify the visible light absorption of the analogues, whatever the pH value. We also show that CpHMD‐then‐QM/MM is capable to qualitatively reproduce the pH‐dependent absorption spectrum of the analogues, despite the employed low QM level of theory.