Disease relevance of dapB

• Nucleotide sequence and expression of the Escherichia coli dapB gene [1].
• The dapB gene was cloned into pBR322 from a transducing lambda bacteriophage, its complete nucleotide sequence established, and the transcriptional start localized [1].
• Regulation of aspartokinase, aspartate semialdehyde dehydrogenase, dihydrodipicolinate synthase and dihydrodipicolinate reductase in Lactobacillus plantarum [2].

High impact information on dapB

• Further studies were performed on an in-frame gene fusion constructed in vitro between the dapB and the lacZ genes [1].
• The DNA sequence predicts that the dapB gene codes for a 273-amino acid polypeptide, Mr 28,798 [1].
• The dapB promoter signals appear to be weak as compared to RNA polymerase consensus sequences [1].
• Finally, dapB gene expression showed a gene dosage effect which suggests that it is not controlled by an element present in limiting amounts in the cell [1].
• Dihydrodipicolinate reductase catalyzes the NAD(P)H-dependent reduction of the alpha,beta-unsaturated cyclic imine dihydrodipicolinate to form the cyclic imine tetrahydrodipicolinate [3].

Chemical compound and disease context of dapB

• 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 [4].
• The three-dimensional structure of Escherichia coli dihydrodipicolinate reductase, complexed with NADPH, has been determined and refined to a crystallographic R-factor of 18.6% with diffraction data to 2.2 A resolution [5].
• Interaction of pyridine nucleotide substrates with Escherichia coli dihydrodipicolinate reductase: thermodynamic and structural analysis of binary complexes [6].

Biological context of dapB

• Expression and purification of dihydrodipicolinate reductase to homogeneity have allowed us to characterize the kinetics, stereochemistry, and chemical mechanism of the enzymatic reaction [7].
• Dihydrodipicolinate reductase uses both NADH and NADPH as cofactors, and analysis of its cofactor binding site allows for a molecular understanding of the enzyme's dual specificity [5].

Associations of dapB with chemical compounds

• DDPR was markedly inhibited by L-lysine [4].
• To elucidate further the regulation of L-lysine biosynthesis in M. methylotrophus, we cloned the genes encoding three other enzymes involved in this pathway, L-aspartate-beta-semialdehyde dehydrogenase, dihydrodipicolinate reductase (DDPR) and diaminopimelate decarboxylase, and examined their properties [4].
• Dihydrodipicolinate reductase catalyzes the NAD(P)H-dependent reduction of the carbon-carbon double bond of the alpha,beta-unsaturated cyclic imine dihydrodipicolinate to form the cyclic imine tetrahydrodipicolinate [7].
• These results allow us to propose a chemical mechanism for the reaction catalyzed by dihydrodipicolinate reductase involving hydride transfer to the beta carbon of the unsaturated imine [7].
• Dihydrodipicolinate reductase is an enzyme found in bacteria and higher plants involved in the biosynthesis of diaminopimelic acid and lysine [5].

Other interactions of dapB

• The aspartate semialdehyde dehydrogenase, dihydrodipicolinate synthase and dihydrodipicolinate reductase were not regulated by the end-products of the pathway [2].

References