Fig. 3.

Ribbon diagram of the BLUF domain of OaPAC, coloured as in Fig. 2. The side-chain of Trp 90 is shown as a stick model, and the prominent kink in the backbone between this residue and the β5-strand is clearly visible. Residues at this point play an important role in signalling at the domain surface the changes that occur around the buried flavin upon photo-excitation