Fig. 5: Structural analyses of AsLOV2 variants.

a Chromophore-binding pocket of wild-type AsLOV2 in its dark-adapted state as revealed by a 1.00 Å crystal structure. b Chromophore-binding pocket of wild-type AsLOV2 in its light-adapted state as revealed by a 1.09 Å crystal structure. c Chromophore-binding pocket of AsLOV2 Q513L in its dark-adapted state as revealed by a 0.90 Å crystal structure. d Chromophore-binding pocket of AsLOV2 Q513L in its light-adapted state as revealed by a 0.98 Å crystal structure. For clarity, helices Cα and Dα are not shown in panels a-d. The Jα helix is drawn in orange, and the flavin- mononucleotide cofactor and key amino acids are highlighted in stick representation. Minor conformations of residues and the flavin nucleotide are drawn in narrower diameter. The active-site cysteine 450 adopts two principal orientations, denoted ‘a’ and ‘b’. In the structures of dark-adapted AsLOV2 wild-type, dark-adapted Q513L, and light-adapted Q513L, orientation ‘b’ splits into two subpopulations with slightly different χ₁ angles. Dashed lines denote hydrogen bonds. e Water density in the interior of dark-adapted AsLOV2 Q513L derived from a 300 ns classical molecular dynamics simulation. The red mesh denotes a density level of 0.3 water molecules per ų. f As e but for light-adapted AsLOV2 Q513L. Corresponding simulations for AsLOV2 wild-type are provided in Suppl. Fig. 13a, b.