Involved in the biosynthesis of the siderophore enterobactin (enterochelin), which is a macrocyclic trimeric lactone of N-(2,3-dihydroxybenzoyl)-serine. The serine trilactone serves as a scaffolding for the three catechol functionalities that provide hexadentate coordination for the tightly ligated iron(2+) atoms. EntE proccesses via a two-step adenylation-ligation reaction (bi-uni-uni-bi ping-pong mechanism). First, it catalyzes the activation of the carboxylate group of 2,3-dihydroxy-benzoate (DHB), via a reversible ATP-dependent pyrophosphate exchange reactions to yield the acyladenylate intermediate 2,3-dihydroxybenzoyl-AMP. It can also transfer AMP to salicylate, 2,4-dihydroxybenzoate, gentisate and 2,3,4-trihydroxybenzoate. In the second step, DHB is transferred from 2,3-dihydroxybenzoyl-AMP onto the phosphopantetheinylated EntB (holo-EntB) to form DHB-holo-EntB. Then this product will serve in the formation of the amide bond between 2,3-dihydroxybenzoate (DHB) and L-serine. It can also transfer adenylated salicylate to holo-EntB. 3 2,3-dihydroxybenzoate + 6 ATP + 3 L-serine = 6 AMP + 6 diphosphate + enterobactin + 4 H(+) 2,3-dihydroxybenzoate + ATP + holo-[aryl-carrier protein] = 2,3-dihydroxybenzoyl-[aryl-carrier protein] + AMP + diphosphate 2,3-dihydroxybenzoyl-5'-AMP + holo-[aryl-carrier protein] = 2,3-dihydroxybenzoyl-[aryl-carrier protein] + AMP + H(+) Inhibited by the adenylate analogs, 5'-O-[N-(salicyl)sulfamoyl]adenosine (Sal-AMS) and 5'-O-[N-(2,3-dihydroxybenzoyl)sulfamoyl]adenosine (DHB-AMS). Adenylation of 2,3-dihydroxybenzoate (DHB) is enhanced by a protein-protein interaction between the EntA and EntE. kcat is 0.3 sec(-1) for 2,3-dihydroxybenzoate-AMP ligase activity with 3-hydroxybenzoate as substrate (at pH 7.8 and 25 degrees Celsius). kcat is 0.8 sec(-1) for 2,3-dihydroxybenzoate-AMP ligase activity with salicylate as substrate (at pH 7.8 and 25 degrees Celsius). kcat is 0.9 sec(-1) for S-dihydroxybenzoyltransferase activity with D-pantetheine as substrate (at pH 7.8 and 25 degrees Celsius). kcat is 2.8 sec(-1) for 2,3-dihydroxybenzoate-AMP ligase activity with ATP and DHB as substrates (at pH 7.8 and 25 degrees Celsius). kcat is 2.8 sec(-1) for S-dihydroxybenzoyltransferase activity with holo-EntB as substrate (at pH 7.8 and 25 degrees Celsius). kcat is 4.4 sec(-1) for 2,3-dihydroxybenzoate-AMP ligase activity with 4-aminosalicylate as substrate (at pH 7.8 and 25 degrees Celsius). kcat is 5.94 sec(-1) for S-dihydroxybenzoyltransferase activity with holo-EntB as substrate (at pH 7.8 and 25 degrees Celsius). kcat is 100 min(-1) for S-dihydroxybenzoyltransferase activity with holo-EntB as substrate (at pH 8.8 and 37 degrees Celsius). kcat is 140 min(-1) for S-dihydroxybenzoyltransferase activity with holo-EntB as substrate. Siderophore biosynthesis; enterobactin biosynthesis. Proteins EntB, EntD, EntE, and EntF form a multienzyme complex called enterobactin synthase. Monomer. EntA and EntE interact together. Under conditions of iron deficiency and by the fur protein. In the absence of holo-EntB, EntE can transfer the adenylate moiety of the 2,3-dihydroxybenzoyl-AMP intermediate to ATP, generating the stress signaling molecule Ap4A involved in the regulation of cell division during oxidative stress, and releasing 2,3-dihydroxybenzoate. It seems that the expression of EntE during iron starvation produces Ap(4)A to slow growth until intracellular iron stores can be restored. Belongs to the ATP-dependent AMP-binding enzyme family. EntE subfamily.