FIGURE 2: Cartoon representation of a TonB dependent transporter involved in Hb piracy. This is ShuA from S. dysenterieae, pdb id: 3fhh. The N-terminal plug domain is coloured purple, the membrane-enclosed beta barrel in light grey and the extracellular loops involved in Hb recognition and haem extraction are rainbow coloured from cyan for loop one to red for loop 11. Two conserved histidine residues proposed to bind to haem are labelled and shown as balls.