Yaroshevich et al. present a chemical reaction mechanism of a 35-kDa blue light-triggered photoreceptor, the Orange Carotenoid Protein (OCP). They find that photoactivation critically involves the transient formation of a protonated ketocarotenoid (oxocarbenium cation) state. This study suggests the role of charge-transfer states during OCP photoconversion.
- Igor A. Yaroshevich
- Eugene G. Maksimov
- Mikhail P. Kirpichnikov