Disease relevance of aroC

• The enzyme chorismate synthase was purified in milligram quantities from an overproducing strain of Escherichia coli [1].
• Chorismate synthase from Staphylococcus aureus [2].
• The chromosomal attachment site for the PA-2 prophage is located between dsd and aroC at the approximately 50 min on the Escherichia coli K-12 genetic map [3].
• Characterization of candidate live oral Salmonella typhi vaccine strains harboring defined mutations in aroA, aroC, and htrA [4].
• The aroC gene of the facultative intracellular pathogen Brucella suis was cloned and sequenced [5].

High impact information on aroC

• We have studied transcript levels of six genes--i.e., two 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase genes, one shikimate kinase gene, one 5-enolpyruvylshikimate 3-phosphate synthase gene, and two chorismate synthase genes--corresponding to four steps of the prechorismate pathway, in cultured tomato cells exposed to fungal elicitors [6].
• Spectroscopic and kinetic characterization of the bifunctional chorismate synthase from Neurospora crassa: evidence for a common binding site for 5-enolpyruvylshikimate 3-phosphate and NADPH [7].
• Chorismate synthase, the last enzyme in the shikimate pathway, catalyzes the transformation of 5-enolpyruvylshikimate 3-phosphate to chorismate, a biochemically unique reaction in that it requires reduced FMN as a cofactor [8].
• Recombinant N. crassa chorismate synthase has a diaphorase activity, i.e. it catalyzes the reduction of oxidized FMN at the expense of NADPH [7].
• Chorismate synthase catalyzes the conversion of 5-enolpyruvylshikimate 3-phosphate (EPSP) to chorismate [9].

Chemical compound and disease context of aroC

• The system is based on Escherichia coli plasmid vectors which contain the DNA fragment, cloned from the chromosome of S. typhimurium C5, which encodes the aroC gene [10].
• Studies with flavin analogs provide evidence that a protonated reduced FMN is the substrate-induced transient intermediate in the reaction of Escherichia coli chorismate synthase [11].
• Escherichia coli chorismate synthase catalyzes the conversion of (6S)-6-fluoro-5-enolpyruvylshikimate-3-phosphate to 6-fluorochorismate. Implications for the enzyme mechanism and the antimicrobial action of (6S)-6-fluoroshikimate [12].
• We report the observation of a deuterium kinetic isotope effect for the conversion of 5-enolpyruvylshikimate-3-phosphate into chorismate (6proR2HV = 1.13 +/- 0.03) using recombinant chorismate synthase from Escherichia coli [13].

Biological context of aroC

• The amino acid sequence was deduced from the nucleotide sequence of the aroC gene and confirmed by determining the N-terminal amino acid sequence of the purified enzyme [1].
• Gene prmB, governing methylation of protein L3 is at minute 50, very close to aroC (98.5% co-transduction) [14].
• The overexpression, purification and complete amino acid sequence of chorismate synthase from Escherichia coli K12 and its comparison with the enzyme from Neurospora crassa [1].
• The S. aureus chorismate synthase was overexpressed to a high level in Escherichia coli using a T7 promoter plasmid construct, the enzyme was purified to near homogeneity in two steps and found to be a homotetramer with a subunit molecular mass, estimated by electrospray mass spectrometry, of 43024 Da [2].
• Characterization of Salmonella enterica derivatives harboring defined aroC and Salmonella pathogenicity island 2 type III secretion system (ssaV) mutations by immunization of healthy volunteers [15].

Anatomical context of aroC

• However, in contrast to the plant enzyme, which is located to the plastid, P. falciparum chorismate synthase is found in the parasite cytosol, akin to the fungal enzymes that possess an intrinsic flavin reductase activity (i.e. are bifunctional) [16].

Associations of aroC with chemical compounds

• On both occasions it took a chromosomal location at minute 50.5 on the linkage map, between aroC and supN, in the region of the dsd genes, which confer the ability to use D-serine as a carbon and energy source [17].
• Chorismate synthase catalyzes the conversion of 5-enolpyruvylshikimate-3-phosphate to chorismate [12].
• The chorismate synthase reaction involves a 1,4-elimination with unusual anti-stereochemistry and requires a reduced flavin cofactor [12].
• The substrate analogue (6S)-6-fluoro-5-enolpyruvylshikimate-3-phosphate is a competitive inhibitor of Neurospora crassa chorismate synthase (Balasubramanian, S., Davies, G. M., Coggins, J. R., and Abell, C. (1991) J. Am. Chem. Soc. 113, 8945-8946) [12].
• On the basis of these findings it is concluded that chorismate synthase preferentially binds neutral flavin species, including the protonated reduced form, rather than anionic flavin species in the presence of EPSP or the 6-fluoro-substrate analog [11].

Other interactions of aroC

• This observed linkage of the gerC genes with the ndk, aroC and aroB genes has been similarly observed in B. subtilis [2].
• Construction of a genetically defined Salmonella typhi Ty2 aroA, aroC mutant for the engineering of a candidate oral typhoid-tetanus vaccine [18].
• Genetic mapping studies show that the mutation mepA is located close to aroC (50 min) and the other mutation, mepB, is very close to malE (91 min) on the chromosome [19].
• DNA was integrated into the S. typhimurium chromosome at aroC by transferring the vectors into S. typhimurium polA mutants and allowing homologous recombination to occur between the cloned and chromosomal aroC genes [10].

Analytical, diagnostic and therapeutic context of aroC

• Molecular cloning and analysis of a cDNA coding for chorismate synthase from the higher plant Corydalis sempervirens Pers [20].
• Binding of the oxidized, reduced, and radical flavin species to chorismate synthase. An investigation by spectrophotometry, fluorimetry, and electron paramagnetic resonance and electron nuclear double resonance spectroscopy [21].
• Purification of chorismate synthase from a cell culture of the higher plant Corydalis sempervirens Pers [22].
• Crystallization and preliminary X-ray crystallographic studies of chorismate synthase from Helicobacter pylori [23].
• In all bacterial and plant species investigated to date, purified CSs lack an FR activity and are correspondingly 8-10 kDa smaller than the N. crassa CS (on the basis of SDS-PAGE) [24].

References