Involved in the biosynthesis of the nonproteinogenic amino acid monomer (S)-3,5-dihydroxyphenylglycine (Dpg) responsible of the production of vancomycin and teicoplanin antibiotics. Catalyzes the syn-addition of a water molecule across the double bond of a trans-2-enoyl-CoA thioester, resulting in the formation of a beta-hydroxyacyl-CoA thioester. Physiologically, DpgD could act as a dehydratase, facilitating the aromatization of the DPA-S-DgpA or DPA-S-CoA intermediate. It can use the non physiological substrates crotonyl-CoA and beta-methylcrotonyl-CoA. a (3S)-3-hydroxyacyl-CoA = a (2E)-enoyl-CoA + H2O a 4-saturated-(3S)-3-hydroxyacyl-CoA = a (3E)-enoyl-CoA + H2O kcat is 1.7 min(-1) for enoyl-CoA-hydratase activity. Antibiotic biosynthesis; vancomycin biosynthesis. Belongs to the enoyl-CoA hydratase/isomerase family.