Figure 1.
Primary steps in the wildtype AsLOV2 photocycle. The dark adapted population (top) has the FMN molecule (with IUPAC atomic labels) bound to the protein via non-covalent interactions. Upon photoexcitation, FMN is promoted to an excited singlet state (right), which persists for 2 ns before generating the excited triplet state (bottom). The FMN triplet state persists for 2.2 μs before forming an adduct between the sulfur on Cys450 and the C4a on FMN (left). The adduct is stable for 85 s before completing the photocycle by recovering the dark adapted population. Inset shows a ribbon diagram of the dark-adapted AsLOV2 structure22 with secondary structure elements labeled and a space-filling view of FMN.