Figure 5

Structure of the modelled active site of Hsa _aTRAcP and that of 1XZW illustrating the difference in the Fe(III) coordination site. Substitution of the sweet potato TRAcP Tyr for His in Hsa _aTRACP (yellow, ball and stick representation) indicates that Hsa _aTRACP is not a member of the TRAcP family as the charge transfer transition required for the purple color is absent.