Disease relevance of ECs5120

• Cloning and nucleotide sequence of the aspartase gene of Escherichia coli W [1].
• Cloning and sequence determination of the aspartase-encoding gene from Brevibacterium flavum MJ233 [2].
• Isolation of a versatile Serratia marcescens mutant as a host and molecular cloning of the aspartase gene [3].
• An amino-acid sequence comparison revealed that Bacillus YM55-1 aspartase shared 71% homology with Bacillus subtilis aspartase and 49% with Escherichia coli and Pseudomonas fluorescens aspartases [4].
• Thermostable aspartase from a marine psychrophile, Cytophaga sp. KUC-1: molecular characterization and primary structure [5].

High impact information on ECs5120

• Fumarase C has sequence homology to the eukaryotic fumarases, aspartase, arginosuccinate lyase, adenylosuccinate lyase and delta-crystallin [6].
• The amino acid sequence of the protein predicted from the nucleotide sequence was consistent with those of the NH2- and COOH-terminal regions and also with the amino acid composition of the purified aspartase determined previously [1].
• Of these regions, the region of Gln96-Gly100 is proposed as a part of the recognition site of the alpha-amino group in L-aspartate for aspartase and the hydroxyl group in L-malate for fumarase [7].
• The regions of Gly228-Glu241 and Val265-Asp272, which form a part of the active-site wall, are suggested to be involved in the allosteric activation of the E.coli aspartase by the binding of the metal ion and the activator [7].
• The aspA structural gene comprises 1431 base-pairs (477 codons excluding the initiation codon), and it encodes a polypeptide of Mr 52190, similar to that predicted from maxicell studies and for the enzyme from E. coli W [8].

Chemical compound and disease context of ECs5120

• It exhibits no allosteric effects, in contrast to the Escherichia coli aspartase, which is activated by divalent metal cation and L-aspartate, but is four-times more active than the E.coli enzyme [7].
• To achieve the direct conversion of fumarate to aspartate, shuttle vectors containing the aspA+ (aspartase) gene of Escherichia coli were constructed [9].
• To elucidate the role of sulfhydryl groups in the enzymatic reaction of the aspartase from Escherichia coli, we used site-directed mutagenesis which showed that the enzyme was activated by replacement of Cys-430 with a tryptophan [10].
• N-(7-Dimethylamino-4-methylcoumarynyl)maleimide (DACM), a fluorescent reagent for sulfhydryl groups, was employed to determine the functionally essential cysteine residues in aspartase from Escherichia coli [11].
• The levels of aspartase, NADP- and NAD-requiring glutamate dehydrogenases (GDHs) in Pseudomonas fluorescens grown under various nutritional conditions were determined [12].

Biological context of ECs5120

• To increase the stability of the aspA plasmid, pNK101 (pBR322::aspA-par) was constructed by using the partition locus (par) derived from the low-copy vector pSC101 [13].
• We report results from preliminary transcription microarray experiments that revealed two previously unknown members of the NarL regulon: the aspA gene encoding aspartate-ammonia lyase, which generates fumarate; and the dcuSR operon encoding the dicarboxylate-responsive regulatory system [14].
• Enzymatic generation of mutant libraries for random mutagenesis of aspartase gene from E. coli J2 was made [15].
• The lack of correspondence between the amplified proteins and the products of other amp-linked genes, aspA and mop(groE), indicated that these genes are not included in the repetitive sequence [16].
• Aspartase purified from Escherichia coli W cells was inactivated by diethylpyrocarbonate following pseudo-first order kinetics [17].

Anatomical context of ECs5120

• Aspartase activity in the immobilized cell column decayed exponentially and uniformly in all sections of a column [18].

Associations of ECs5120 with chemical compounds

• A list of potential active site residues has been generated based on their proximity to this active site lysine, sequence homology comparisons with other members of the aspartase-fumarase enzyme family, and the necessity for chemically reasonable functionalities for the proposed roles [19].
• Addition of glucose to Asp-C medium decreased aspartase formation [20].
• Acid-base chemical mechanism of aspartase from Hafnia alvei [21].
• Activation of aspartase by glycerol [22].
• By using site directed mutagenesis, the aspartase was activated by replacement of Lys-126 with an arginine residue [15].

Analytical, diagnostic and therapeutic context of ECs5120

• The aspA product was determined to have a size of approx. 57 kDa by SDS-PAGE [2].
• Activation of aspartase by site-directed mutagenesis [10].
• The native molecular weight of aspartase determined by gel filtration was about 200,000, and this enzyme was composed of four identical monomers with molecular weights of 51,000 determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis [23].
• The guanidine-HCl (Gu-HCl)-induced denaturation of a tetrameric enzyme, aspartase from Escherichia coli has been studied by size-exclusion chromatography, and circular dichroism and fluorescence spectroscopies [24].
• Random mutagenesis was performed on an Escherichia coli aspartase gene (aspA) by error-prone PCR to construct a mutant library [25].

References