Figure 1

Ribbon diagrams of the BLUF domain crystal structures from WT (A, pdb:1yrx) and C20S (B, pdb:2iyg) AppABLUF domains showing W104 in the vicinity of the flavin in the Trpin conformation (A) and away from the flavin in the Trpout conformation (B). Important residues involved in an H-bond network around the flavin (Y21, H44, N45, Q63) are shown. Dashed lines represent H-bonds between the flavin and the residues.