American Chemical Society
jp6b04963_si_003.mpg (5.95 MB)

Reverse Stability of Oxyluciferin Isomers in Aqueous Solutions

Download (5.95 MB)
posted on 2016-08-01, 00:00 authored by Yoshifumi Noguchi, Miyabi Hiyama, Motoyuki Shiga, Osamu Sugino, Hidefumi Akiyama
We investigated the stability of oxyluciferin anions (keto, enol, and enolate isomers) in aqueous solution at room temperature by performing a nanosecond time scale first-principles molecular dynamics simulation. In contrast to all previous quantum chemistry calculations, which suggested the keto-type to be the most stable, we show that the enol-type is slightly more stable than the keto-type, in agreement with some recent experimental studies. The simulation highlights the remarkable hydrophobicity of the keto-type by the cavity formed at the oxyluciferin–water interface as well as a reduction in hydrophobicity with the number of hydrating water molecules. It is therefore predicted that the isomeric form in a hydrated cluster is size-dependent.