A Secondary β Deuterium Kinetic Isotope Effect in the Chorismate Synthase Reaction

Bornemann, Stephen; Theoclitou, Maria‐Elena; Brüne, Martin; Webb, Martin R.; Thorneley, R. N. F.; Abell, Chris

doi:10.1006/bioo.2000.1174

Cited by 16 publications

(21 citation statements)

References 31 publications

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“…Kinetic and mechanistic studies have accumulated substantial evidence for a radical mechanism in which the reduced, enzyme-bound FMN facilitates C-O bond cleavage by transient electron donation to the substrate (6,7,9,25). The proposed radical chemistry for the reaction has been supported by theoretical considerations (26).…”

Section: Discussionmentioning

confidence: 99%

Mechanism of Chorismate Synthase

Kitzing¹,

Auweter²,

Amrhein

et al. 2004

Journal of Biological Chemistry

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Chorismate synthase catalyzes the last step in the common shikimate pathway leading to aromatic compounds such as the aromatic amino acids. The reaction consists of the 1,4-anti-elimination of the 3-phosphate group and the C-(6proR) hydrogen from 5-enolpyruvylshikimate 3-phosphate to yield chorismate. Although this reaction does not involve a net redox change, the enzyme has an absolute requirement for reduced flavin mononucleotide, which is not consumed during the reaction. Two invariant histidine residues are found in the active site of the enzyme: His 17 and His 106 . Using sitedirected mutagenesis, both histidines were replaced by alanine, reducing the activity 10-and 20-fold in the H106A and H17A mutant protein, respectively. Based on the characterization of the two single mutant proteins, it is proposed that His 106 serves to protonate the monoanionic reduced FMN, whereas His 17 protonates the leaving phosphate group of the substrate. An enzymatic reaction mechanism in keeping with the experimental results is presented.Chorismate synthase catalyzes the last step in the shikimate pathway leading to the branch point metabolite chorismate, which is utilized in a number of enzymatic transformations toward the biosynthesis of aromatic compounds such as the aromatic amino acids tyrosine, phenylalanine, and tryptophan (for a recent review, see Ref.

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Section: Discussionmentioning

confidence: 99%

Mechanism of Chorismate Synthase

Kitzing¹,

Auweter²,

Amrhein

et al. 2004

Journal of Biological Chemistry

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“…5-(1-carboxyvinyl)-3-phosphoshikimic acid (Figure 15). The transformation of 5-(1-carboxyvinyl)-3-phosphoshikimic acid to chorismic acid involves a 1,4-elimination of phosphoric acid by chorismate synthase (EC 4.2.3.5) (Figure 16) (FLOSS et al 1972;BORNEMANN et al 1996BORNEMANN et al , 2000JAKEMAN et al 1998;LEWIS et al 1999;OSBORNE et al 2000;IUBMB 2001). …”

Section: Hsmentioning

confidence: 99%

Biosynthesis of food constituents: Amino acids: 2. The alanine-valine-leucine, serine-cysteine-glycine, and aromatic and heterocyclic amino acids groups - a review

Velı́šek¹,

Cejpek²

2006

Czech J. Food Sci.

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This review article gives a survey of principal pathways that lead to the biosynthesis of the proteinogenic amino acids of the alanine-valine-leucine group starting with pyruvic acid from the glycolytic pathway and serine-cysteine-glycine group starting with 3-phospho-D-glyceric acid from the glycolytic pathway. A survey is further given to the aromatic and heterocyclic amino acids (phenylalanine, tyrosine, tryptophan, histidine) starting with 3-phosphoenolpyruvic acid from the glycolytic pathway and D-erythrose 4-phosphate, an intermediate in the pentose phosphate cycle and Calvin cycle.

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“…18 It has been suggested that C(6) -H cleavage most likely follows C(3) -O cleavage in a non-concerted radical or E1 reaction mechanism and C(6)-H cleavage is irreversible. 18 It has also been suggested that the enzyme must tightly control the deprotonation at pro R C-6 with an appropriately positioned active site base. 18 Studies with substrate and cofactor analogs provided strong evidence for a radical mechanism.…”

Section: Introductionmentioning

confidence: 99%

“…18 It has also been suggested that the enzyme must tightly control the deprotonation at pro R C-6 with an appropriately positioned active site base. 18 Studies with substrate and cofactor analogs provided strong evidence for a radical mechanism. 19 Furthermore, a possible regulation of the enzyme activity by means of the availability of reduced FMN remains poorly understood.…”

Section: Introductionmentioning

confidence: 99%

Crystal Structure of Chorismate Synthase: A Novel FMN-binding Protein Fold and Functional Insights

Ahn

Yoon

Lee

et al. 2004

Journal of Molecular Biology

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Chorismate synthase catalyzes the conversion of 5-enolpyruvylshikimate 3-phosphate to chorismate in the shikimate pathway, which represents an attractive target for discovering antimicrobial agents and herbicides. Chorismate serves as a common precursor for the synthesis of aromatic amino acids and many aromatic compounds in microorganisms and plants. Chorismate synthase requires reduced FMN as a cofactor but the catalyzed reaction involves no net redox change. Here, we have determined the crystal structure of chorismate synthase from Helicobacter pylori in both FMN-bound and FMN-free forms. It is a tetrameric enzyme, with each monomer possessing a novel "beta-alpha-beta sandwich fold". Highly conserved regions, including several flexible loops, cluster together around the bound FMN to form the active site. The unique FMN-binding site is formed largely by a single subunit, with a small contribution from a neighboring subunit. The isoalloxazine ring of the bound FMN is significantly non-planar. Our structure illuminates the essential functional roles played by the cofactor.

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A Secondary β Deuterium Kinetic Isotope Effect in the Chorismate Synthase Reaction

Cited by 16 publications

References 31 publications

Mechanism of Chorismate Synthase

Mechanism of Chorismate Synthase

Biosynthesis of food constituents: Amino acids: 2. The alanine-valine-leucine, serine-cysteine-glycine, and aromatic and heterocyclic amino acids groups - a review

Crystal Structure of Chorismate Synthase: A Novel FMN-binding Protein Fold and Functional Insights

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