Disease relevance of dapA

• Chromosomal location and nucleotide sequence of the Escherichia coli dapA gene [1].
• Previously, we showed that the enzymes aspartokinase (AK) and dihydrodipicolinate synthase (DDPS), which are involved in L-lysine biosynthesis in the Gram-negative obligate methylotroph Methylophilus methylotrophus AS1, were inhibited by allosteric effectors, including L-lysine [2].
• Overproduction of L-Lysine from methanol by Methylobacillus glycogenes derivatives carrying a plasmid with a mutated dapA gene [3].
• Lysine-feedback-insensitive bacterial DHDPS and AK enzymes encoded by the Corynebacterium dapA gene and a mutant E. coli lysC gene, respectively, were linked to a chloroplast transit peptide and expressed from a seed-specific promoter in transgenic canola and soybean seeds [4].
• Regulation of aspartokinase, aspartate semialdehyde dehydrogenase, dihydrodipicolinate synthase and dihydrodipicolinate reductase in Lactobacillus plantarum [5].

High impact information on dapA

• Transcription initiation sites associated with the orfY-orfX-asd-dapG-dapA gene cluster were mapped by primer extension [6].
• Functional rescue of a bacterial dapA auxotroph with a plant cDNA library selects for mutant clones encoding a feedback-insensitive dihydrodipicolinate synthase [7].
• In plants and bacteria, the branch point of (S)-lysine biosynthesis is the condensation of (S)-aspartate-beta-semialdehyde [(S)-ASA] and pyruvate, a reaction catalyzed by dihydrodipicolinate synthase (DHDPS, EC 4.2.1.52) [8].
• Role of arginine 138 in the catalysis and regulation of Escherichia coli dihydrodipicolinate synthase [8].
• Dihydrodipicolinate synthase (DHDPS) catalyzes the condensation of pyruvate with L-aspartate beta-semialdehyde [9].

Chemical compound and disease context of dapA

• In Escherichia coli, the first enzyme of the diaminopimelate and lysine pathway is dihydrodipicolinate synthetase, which is feedback-inhibited by lysine and encoded by the dapA gene [1].
• We show here that this is not the case and that expression of LacZ from the dapA promoter (PdapA) increases in response to diaminopimelic acid limitation in E. coli K-12 [10].
• A similar increase of the flow of aspartate semialdehyde to lysine was found in strains with increased dihydrodipicolinate synthase activity, constructed by introducing the dapA gene of Escherichia coli (coding for the synthase) into C. glutamicum [11].
• Based on this and our previous results, we constructed an L-lysine-producing strain of M. methylotrophus by introducing well-characterized genes encoding desensitized forms of AK and DDPS, as well as dapB (encoding DDPR) from Escherichia coli, using a broad host range plasmid [2].

Biological context of dapA

• The complete nucleotide sequence and the transcriptional start of the dapA gene were determined [1].
• The results show that dapA consists of a single cistron encoding a 292-amino acid polypeptide of 31,372 daltons [1].
• Cloning and sequence analysis of the region located downstream of the dapA gene of Escherichia coli has revealed the presence of an open reading frame that is cotranscribed with dapA [12].
• The putative transcription termination signals of the dapA-nlpB operon overlap the promoter of the adjacent purC gene [12].
• Subcloning of parental cosmids in dapA, dapD, and lysA mutants of E. coli localized these genes, respectively, within 1.4, 3.4, and 1.8 kb fragments, cloned in an E. coli/C. glutamicum shuttle vector [13].

Associations of dapA with chemical compounds

• AL119 containing the dapA gene produced 8 g of L-lysine per liter in a 5-liter jar fermentor from methanol as a substrate [3].
• The incorporation of cystathionine into peptidoglycan metabolism was examined with a dapA metC mutant, whereas for lanthionine, a dapA metA mutant strain was used [14].
• These chromosomal constructions generate dapA and thyA knockouts, which lead to diaminopimelate or thymidine auxotrophies, respectively, and they serve to provide absolute counterselection even in rich media [15].
• These include the complexes of DHDPS with (1) pyruvate, (2) pyruvate and the L-aspartate beta-semialdehyde analog succinate beta-semialdehyde, (3) the inhibitor alpha-ketopimelic acid, (4) dipicolinic acid, and (5) the natural feedback inhibitor L-lysine [9].
• DHDPS is 50% inhibited by 1.0 mM-L-lysine, 1.2 mM-sodium dipicolinate or 4.6 mM-S-2-aminoethyl-L-cysteine [16].

Analytical, diagnostic and therapeutic context of dapA

• Escherichia coli dihydrodipicolinate synthase. Identification of the active site and crystallization [16].
• Reaction mechanism of Escherichia coli dihydrodipicolinate synthase investigated by X-ray crystallography and NMR spectroscopy [9].

References