title: Escherichia coli dihydrodipicolinate synthase. Identification of the active site and crystallization.
abstract: Escherichia coli dihydrodipicolinate synthase (DHDPS) (EC 4.2.1.52), the first enzyme unique to lysine biosynthesis, catalyses the condensation of pyruvate and aspartate beta-semialdehyde (ASA) by a ping-pong mechanism. Pyruvate binds first to the enzyme, forming a Schiff base with the epsilon-amino group of Lys-161, followed by binding of ASA. Km values of 0.57 and 0.55 mM were determined for pyruvate and DL-ASA respectively. 3-Bromopyruvate inhibits DHDPS with a Ki of 1.6 mM. DHDPS is 50% inhibited by 1.0 mM-L-lysine, 1.2 mM-sodium dipicolinate or 4.6 mM-S-2-aminoethyl-L-cysteine. Crystals of DHDPS diffracting to beyond a resolution of 0.24 nm (2.4 A) were obtained under several experimental conditions. Diffraction patterns were compatible with trigonal space groups P3(1)21 or P3(2)21, with unit-cell parameters a = b = 12.26 nm and c = 11.19 nm. The density of the crystals indicates the presence of a dimer of DHDPS subunits per asymmetric unit.
authors.affiliation: Max-Planck-Institute für Biochemie, Martinsried, Federal Republic of Germany.
authors.forename: B
authors.initials: B
authors.lastname: Laber
authors.forename: F X
authors.initials: FX
authors.lastname: Gomis-Rüth
authors.forename: M J
authors.initials: MJ
authors.lastname: Romão
authors.forename: R
authors.initials: R
authors.lastname: Huber
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002845:Chromatography; D003461:Crystallography; D004926:Escherichia coli / Q000201:enzymology*; D006836:Hydro-Lyases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000302:isolation & purification / Q000648:ultrastructure; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments / Q000737:chemistry; D016415:Sequence Alignment; D014961:X-Ray Diffraction
chemical_list: D010446:Peptide Fragments; D006836:Hydro-Lyases; C020040:4-hydroxy-tetrahydrodipicolinate synthase