Publications

• Polyglutamylation of folate coenzymes is necessary for methionine biosynthesis and maintenance of intact mitochondrial genome in Saccharomyces cerevisiae.

  Cherest H., Thomas D., Surdin-Kerjan Y.

  One-carbon metabolism is essential to provide activated one-carbon units in the biosynthesis of methionine, purines, and thymidylate. The major forms of folates in vivo are polyglutamylated derivatives. In organisms that synthesize folate coenzymes de novo, the addition of the glutamyl side chains ... >> More

  One-carbon metabolism is essential to provide activated one-carbon units in the biosynthesis of methionine, purines, and thymidylate. The major forms of folates in vivo are polyglutamylated derivatives. In organisms that synthesize folate coenzymes de novo, the addition of the glutamyl side chains is achieved by the action of two enzymes, dihydrofolate synthetase and folylpolyglutamate synthetase. We report here the characterization and molecular analysis of the two glutamate-adding enzymes of Saccharomyces cerevisiae. We show that dihydrofolate synthetase catalyzing the binding of the first glutamyl side chain to dihydropteroate yielding dihydrofolate is encoded by the YMR113w gene that we propose to rename FOL3. Mutant cells bearing a fol3 mutation require folinic acid for growth and have no dihydrofolate synthetase activity. We show also that folylpolyglutamate synthetase, which catalyzes the extension of the glutamate chains of the folate coenzymes, is encoded by the MET7 gene. Folylpolyglutamate synthetase activity is required for methionine synthesis and for maintenance of mitochondrial DNA. We have tested whether two folylpolyglutamate synthetases could be encoded by the MET7 gene, by the use of alternative initiation codons. Our results show that the loss of mitochondrial functions in met7 mutant cells is not because of the absence of a mitochondrial folylpolyglutamate synthetase. << Less

  J. Biol. Chem. 275:14056-14063(2000) [PubMed] [EuropePMC]

• Folates and one-carbon metabolism in plants and fungi.

  Cossins E.A., Chen L.

  Folate-dependent pathways of one-carbon metabolism are essential for the synthesis of purines, formylmethionyl-tRNA, thymidylate, serine and methionine. These syntheses use a cellular source of one-carbon substituted, tetrahydrofolate polyglutamate derivatives which are the preferred substrates of ... >> More

  Folate-dependent pathways of one-carbon metabolism are essential for the synthesis of purines, formylmethionyl-tRNA, thymidylate, serine and methionine. These syntheses use a cellular source of one-carbon substituted, tetrahydrofolate polyglutamate derivatives which are the preferred substrates of most folate-dependent enzymes. In the last decade, there have been major advances in the folate biochemistry of animal, bacterial, fungal and plant systems. These have included the refinement of methods for folate isolation and characterization, basic work on key enzymes of folate biosynthesis and the detailed characterization of proteins that catalyze the generation and utilization of one-carbon substituted folates. << Less

  Phytochemistry 45:437-452(1997) [PubMed] [EuropePMC]

• Tetrahydrofolate biosynthesis in plants: molecular and functional characterization of dihydrofolate synthetase and three isoforms of folylpolyglutamate synthetase in Arabidopsis thaliana.

  Ravanel S., Cherest H., Jabrin S., Grunwald D., Surdin-Kerjan Y., Douce R., Rebeille F.

  Tetrahydrofolate coenzymes involved in one-carbon (C1) metabolism are polyglutamylated. In organisms that synthesize tetrahydrofolate de novo, dihydrofolate synthetase (DHFS) and folylpolyglutamate synthetase (FPGS) catalyze the attachment of glutamate residues to the folate molecule. In this stud ... >> More

  Tetrahydrofolate coenzymes involved in one-carbon (C1) metabolism are polyglutamylated. In organisms that synthesize tetrahydrofolate de novo, dihydrofolate synthetase (DHFS) and folylpolyglutamate synthetase (FPGS) catalyze the attachment of glutamate residues to the folate molecule. In this study we isolated cDNAs coding a DHFS and three isoforms of FPGS from Arabidopsis thaliana. The function of each enzyme was demonstrated by complementation of yeast mutants deficient in DHFS or FPGS activity, and by measuring in vitro glutamate incorporation into dihydrofolate or tetrahydrofolate. DHFS is present exclusively in the mitochondria, making this compartment the sole site of synthesis of dihydrofolate in the plant cell. In contrast, FPGS is present as distinct isoforms in the mitochondria, the cytosol, and the chloroplast. Each isoform is encoded by a separate gene, a situation that is unique among eukaryotes. The compartmentation of FPGS isoforms is in agreement with the predominance of gamma-glutamyl-conjugated tetrahydrofolate derivatives and the presence of serine hydroxymethyltransferase and C1-tetrahydrofolate interconverting enzymes in the cytosol, the mitochondria, and the plastids. Thus, the combination of FPGS with these folate-mediated reactions can supply each compartment with the polyglutamylated folate coenzymes required for the reactions of C1 metabolism. Also, the multicompartmentation of FPGS in the plant cell suggests that the transported forms of folate are unconjugated. << Less

  Proc. Natl. Acad. Sci. U.S.A. 98:15360-15365(2001) [PubMed] [EuropePMC]

• THE BIOSYNTHESIS OF FOLIC ACID. III. ENZYMATIC FORMATION OF DIHYDROFOLIC ACID FROM DIHYDROPTEROIC ACID AND OF TETRAHYDROPTEROYLPOLYGLUTAMIC ACID COMPOUNDS FROM TETRAHYDROFOLIC ACID.

  GRIFFIN M.J., BROWN G.M.

  J Biol Chem 239:310-316(1964) [PubMed] [EuropePMC]

• Folylpoly-gamma-glutamate synthetase-dihydrofolate synthetase. Cloning and high expression of the Escherichia coli folC gene and purification and properties of the gene product.

  Bognar A.L., Osborne C., Shane B., Singer S.C., Ferone R.

  The Escherichia coli gene for folylpolyglutamate synthetase-dihydrofolate synthetase was localized to plasmids pLC22-45, 24-31, and 28-44 of the Clarke-Carbon E. coli colony bank (Clarke, L., and Carbon, J. (1976) Cell 9, 91-99) by screening the bank by replica mating with an E. coli folC mutant. ... >> More

  The Escherichia coli gene for folylpolyglutamate synthetase-dihydrofolate synthetase was localized to plasmids pLC22-45, 24-31, and 28-44 of the Clarke-Carbon E. coli colony bank (Clarke, L., and Carbon, J. (1976) Cell 9, 91-99) by screening the bank by replica mating with an E. coli folC mutant. The folC gene was subcloned from pLC22-45 and inserted into a high copy number plasmid containing the lambda replication control region under the control of the temperature-sensitive cI857 repressor and into a high expression plasmid containing the lambda PL promoter and the cI857 repressor. The folC structural gene was located on a 1.52-kilobase PvuI fragment, sufficient to code for a protein of maximum Mr 55,000. E. coli transformants containing the recombinant plasmids, when induced by culturing at 42 degrees C, had folylpolyglutamate synthetase and dihydrofolate synthetase levels that were 100-to 400-fold higher than in wild type strains and which represented up to 4% of the soluble cell protein. The E. coli folylpolyglutamate synthetase-dihydrofolate synthetase has been purified to homogeneity from the transformants. Both activities are catalyzed by a single protein of Mr 47,000. Some kinetic properties of the enzymes and a new spectrophotometric method for assaying dihydrofolate synthetase activity are described. << Less

  J. Biol. Chem. 260:5625-5630(1985) [PubMed] [EuropePMC]

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