Fig. 2.

Alignment of the protein sequence of Tet(X4) with other TetX variants. The strictly conserved amino acid residues are boxed in red. Physicochemically similar amino acids are shown in red. FAD-binding sites are indicated by a solid circle (•); substrate recognition sites are indicated by black stars (*); residue P³¹⁸ is the key site for FAD and substrate binding and is depicted as a solid inverted triangle (▼). The figure was prepared using CLUSTAL Omega [16] and ESPript [17]