InterPro: IPR005263 Dihydrodipicolinate synthase subfamily

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, IPR005264) (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.

This family represents a subclass of dihydrodipicolinate synthase.