The Effect of dynamical fluctuations of hydration structures on the absorption spectra of oxyluciferin anions in an aqueous solution

Hiyama, Miyabi*; Shiga, Motoyuki; Koga, Nobuaki*; Sugino, Osamu*; Akiyama, Hidefumi*; Noguchi, Yoshifumi*

Physical Chemistry Chemical Physics, 19(15), p.10028 - 10035, 2017/04

https://doi.org/10.1039/C7CP01067B

In this study, the effect of hydration on the absorption spectra of oxyluciferin anion isomers in an aqueous solution is investigated for elucidating the influence of characteristic hydration structures. Using a canonical ensemble of hydration structures obtained from first-principles molecular dynamics simulations, the instantaneous absorption spectra of keto-, enol-, and enolate-type aqueous oxyluciferin anions at room temperature are computed from a collection of QM/MM calculations using an explicit solvent. It is demonstrated that the calculations reproduce experimental results concerning spectral shifts and broadening, for which traditional methods based on quantum chemistry and the Franck-Condon approximation fail because of the molecular vibrations of oxyluciferin anions and dynamical fluctuations of their hydration structures.