Disease relevance of betB

• The deduced amino acid sequence of the DNA fragment cloned from Tn5G19 exhibits 84% identity with the betB gene product of E. coli that has betaine aldehyde dehydrogenase activity [1].
• Rapid purification and properties of betaine aldehyde dehydrogenase from Pseudomonas aeruginosa [2].

High impact information on betB

• Also, consistent with a disruption of betB in Tn5G19, choline inhibited growth of this strain in media containing 0.7 M NaCl, while glycine-betaine restores growth to wild-type levels [1].
• The orp gene is located between 0.6 to 6.6 min while betB is located between 10.5 to 12.5 min on the chromosome of PAO1 [1].
• Unlike the parental strain, the Tn5G19 mutant could not utilize choline as a sole carbon, nitrogen and energy source, and it was deficient in betaine aldehyde dehydrogenase activity [1].
• Although E. coli BADH was specific for the substrate, betaine aldehyde, it showed the highest levels of similarity to the prototype human ALDH-2 [3].
• An open reading frame of 1476 nucleotides, cloned from a region of the Escherichia coli genome encoding betaine biosynthesis functions, was shown to encode a betaine aldehyde dehydrogenase (BADH; EC 1.2.1.8) [3].

Chemical compound and disease context of betB

• With the ambition to transfer the betaine biosynthetic pathway into plants not capable of synthesizing this osmoprotectant, the Escherichia coli gene betB encoding the second enzyme in the pathway, betaine-aldehyde dehydrogenase was introduced into Nicotiana tabacum [4].
• The deduced primary structure of the E. coli BADH showed 39-43% positional identity, over its entire length, to aldehyde dehydrogenases (ALDH: EC 1.2.1.3) of mammalian origin [3].
• Betaine aldehyde dehydrogenase from Pseudomonas aeruginosa: cloning, over-expression in Escherichia coli, and regulation by choline and salt [5].
• In the human pathogen Pseudomonas aeruginosa, betaine aldehyde dehydrogenase (BADH) may play a dual role assimilating carbon and nitrogen from choline or choline precursors-abundant at infection sites-and producing glycine betaine, which protects the bacteria against the high-osmolarity stress prevalent in the infected tissues [5].
• Site-directed mutagenesis and homology modeling indicate an important role of cysteine 439 in the stability of betaine aldehyde dehydrogenase from Pseudomonas aeruginosa [6].

Biological context of betB

• In addition to the homology with E. coli genes, the deduced sequence of the sinorhizobial BADH protein displays consensus sequences also found in plant BADHs [7].
• The osmoregulatory NAD-dependent betaine aldehyde dehydrogenase (betaine aldehyde:NAD oxidoreductase, EC 1.2.1.8), of Escherichia coli, was purified to apparent homogeneity from an over-producing strain carrying the structural gene for the enzyme (betB) on the plasmid vector pBR322 [8].

Associations of betB with chemical compounds

• Plants producing both CDH and BADH generally accumulated higher amounts of glycine betaine than plants producing CDH alone, as determined by 1H NMR analysis [9].
• The spinach E103K mutant was almost inactive, whereas the E103Q mutant showed a similar activity for the oxidation of betaine aldehyde to that of wild type BADH, but a lower affinity for omega-aminoaldehydes [10].
• As there were significant amounts of BADH protein and activity in P. aeruginosa cells grown on glucose plus choline, as well as the BADH activity exhibiting tolerance to salt, it is likely that glycine betaine is synthesized in vivo and could play an important osmoprotectant role under conditions of infection [5].

Analytical, diagnostic and therapeutic context of betB

• Analytical ultracentrifugation, gel filtration, chemical cross-linking, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis suggest that BADH from P. aeruginosa is a homodimer with 61-kDa subunits [2].
• Molecular cloning and functional characterization of two kinds of betaine-aldehyde dehydrogenase in betaine-accumulating mangrove Avicennia marina (Forsk.) Vierh [11].

References