Involved in the biosynthesis of the siderophore enterobactin (enterochelin), which is a macrocyclic trimeric lactone of N-(2,3-dihydroxybenzoyl)-serine. EntF catalyzes the activation of L-serine via ATP-dependent PPi exchange reaction to form seryladenylate. Activated L-serine is loaded onto the peptidyl carrier domain via a thioester linkage to the phosphopanthetheine moiety, forming seryl-S-Ppant-EntF. EntF acts then as the sole catalyst for the formation of the three amide and three ester linkages found in enterobactin, using seryladenylate and 2,3-dihydroxybenzoate-S-Ppant-EntB (DHB-S-Ppant-EntB) as substrates, via the formation of a DHB-Ser-S-Ppant-EntF intermediate. 3 2,3-dihydroxybenzoate + 6 ATP + 3 L-serine = 6 AMP + 6 diphosphate + enterobactin + 4 H(+) ATP + holo-[peptidyl-carrier protein] + L-serine = AMP + diphosphate + L-seryl-[peptidyl-carrier protein] Binds 1 phosphopantetheine covalently. Siderophore biosynthesis; enterobactin biosynthesis. Proteins EntB, EntD, EntE and EntF are the component of the enterobactin synthase. Components probably do not form a stable complex. EntF acts as a catalytic monomer. Membrane-associated. 4'-phosphopantetheine is transferred from CoA to a specific serine of apo-EntF by EntD. Holo-EntF so formed is then acylated with seryl-AMP. Belongs to the ATP-dependent AMP-binding enzyme family. EntF subfamily.