This enzyme complex catalyses the conversion of three molecules each of 2,3-dihydroxybenzoate and?L-serine to form the siderophore enterobactin. In?Escherichia coli?the complex is formed by EntB (an aryl carrier protein that has to be activated by 4′-phosphopantetheine), EntD (a phosphopantetheinyl transferase that activates EntB), EntE (catalyses the ATP-dependent condensation of 2,3-dihydroxybenzoate and holo-EntB to form the covalently arylated form of EntB), and EntF (a four domain protein that catalyses the activation of?L-serine by ATP, the condensation of the activated?L-serine with the activated 2,3-dihydroxybenzoate, and the trimerization of three such moieties to a single enterobactin molecule).
