Catalyzes the hydrolysis of N-((2S)-2-amino-2-carboxyethyl)-L-glutamate (ACEGA) to form L-2,3-diaminopropionic acid and 2-oxoglutarate. Involved in the biosynthesis of L-2,3-diaminopropionic acid (L-Dap), a precursor of staphyloferrin B and antibiotics. H2O + N-[(2S)-2-amino-2-carboxyethyl]-L-glutamate + NAD(+) = (S)-2,3-diaminopropanoate + 2-oxoglutarate + H(+) + NADH Siderophore biosynthesis. Homodimer. Up-regulated under iron-deficient growth conditions. Repressed by Fur under iron-rich growth conditions. Mutation results in abrogation of synthesis of staphyloferrin B. Belongs to the ornithine cyclodeaminase/mu-crystallin family.