InterPro domain: IPR002220

Dihydrodipicolinate synthase (EC 4.2.1.52) (DHDPS, DapA) catalyses, in higher plants, some fungi and bacteria (gene dapA), the first reaction specific to the biosynthesis of lysine and of diaminopimelate [ 1 ]. DHDPS is responsible for the condensation of aspartate semialdehyde and pyruvate by a ping-pong mechanism in which pyruvate first binds to the enzyme by forming aSchiff-base with a lysine residue [ 2 , 3 ].

Other proteins are structurally related to DHDPS and probably also actvia a similar catalytic mechanism [ 4 ]:

• Escherichia coli N-acetylneuraminate lyase (EC 4.1.3.3) (gene nanA), which catalyses the condensation of N-acetyl-D-mannosamine and pyruvate to form N-acetylneuraminate.
• Trans-o-hydroxybenzylidenepyruvate hydratase-aldolase.
• D-4-deoxy-5-oxoglucarate dehydratase.
• Rhizobium meliloti protein mosA [ 5 ], which is involved in the biosynthesis of the rhizopine 3-o-methyl-scyllo-inosamine.
• Thermoproteus tenax 2-dehydro-3-deoxy-D-gluconate/2-dehydro-3-deoxy-phosphogluconate aldolase (KdgA) [ 6 ].

1. Cloning, expression, purification and crystallization of dihydrodipicolinate synthase from Agrobacterium tumefaciens. Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun. 68, 1040-7
2. Escherichia coli dihydrodipicolinate synthase. Identification of the active site and crystallization. Biochem. J. 288 ( Pt 2), 691-5
3. New insights into the mechanism of dihydrodipicolinate synthase using isothermal titration calorimetry. Biochimie 92, 254-62
4. Structure and mechanism of a sub-family of enzymes related to N-acetylneuraminate lyase. J. Mol. Biol. 266, 381-99
5. The Rhizobium meliloti rhizopine mos locus is a mosaic structure facilitating its symbiotic regulation. J. Bacteriol. 175, 5193-204
6. Crystal structure and stereochemical studies of KD(P)G aldolase from Thermoproteus tenax. Proteins 72, 35-43