InterPro: IPR002220 Dihydrodipicolinate synthetase

Dihydropicolinate synthase (DHDPS) is the key enzyme in lysine biosynthesis via the diaminopimelate pathway of prokaryotes, some phycomycetes and higher plants. The enzyme catalyses the condensation of L-aspartate-beta- semialdehyde and pyruvate to dihydropicolinic acid via a ping-pong mechanism in which pyruvate binds to the enzyme by forming a Schiff-base with a lysine residue [1]. Three other proteins are structurally related to DHDPS and probably also act via a similar catalytic mechanism. These are Escherichia coli N-acetylneuraminate lyase (EC:4.1.3.3) (gene nanA), which catalyzes the condensation of N-acetyl-D-mannosamine and pyruvate to form N-acetylneuraminate; Rhizobium meliloti (Sinorhizobium meliloti) protein mosA [2], which is involved in the biosynthesis of the rhizopine 3-o-methyl-scyllo-inosamine; and E. coli hypothetical protein yjhH. The sequences of DHDPS from different sources are well-conserved. The structure takes the form of a homotetramer, in which 2 monomers are related by an approximate 2-fold symmetry [1]. Each monomer comprises 2 domains: an 8-fold alpha-/beta-barrel, and a C-terminal alpha-helical domain. The fold resembles that of N-acetylneuraminate lyase. The active site lysine is located in the barrel domain, and has access via 2 channels on the C-terminal side of the barrel.