Publications

• The biosynthesis of folic acid. IX. Purification and properties of the enzymes required for the formation of dihydropteroic acid.

  Richey D.P., Brown G.M.

  J. Biol. Chem. 244:1582-1592(1969) [PubMed] [EuropePMC]

• Purification and partial characterization of 7,8-dihydro-6-hydroxymethylpterin-pyrophosphokinase and 7,8-dihydropteroate synthase from Escherichia coli MC4100.

  Talarico T.L., Dev I.K., Dallas W.S., Ferone R., Ray P.H.

  The enzymes 7,8-dihydroxymethylpterin-pyrophosphokinase (HPPK) and 7,8-dihydropteroate synthase (DHPS), which act sequentially in the folate pathway, were purified to homogeneity from crude extracts of Escherichia coli MC4100. The enzymes represent less than 0.01% of the total soluble protein. HPP ... >> More

  The enzymes 7,8-dihydroxymethylpterin-pyrophosphokinase (HPPK) and 7,8-dihydropteroate synthase (DHPS), which act sequentially in the folate pathway, were purified to homogeneity from crude extracts of Escherichia coli MC4100. The enzymes represent less than 0.01% of the total soluble protein. HPPK was purified greater than 10,000-fold; the native enzyme appears to be a monomer with a molecular mass of 25 kDa and a pI of 5.2. DHPS was purified greater than 7,000-fold; the native enzyme has an apparent molecular mass of 52 to 54 kDa and is composed of two identical 30-kDa subunits. The amino-terminal sequences for both enzymes have been determined. << Less

  J. Bacteriol. 173:7029-7032(1991) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• A bifunctional protein in the folate biosynthetic pathway of Streptococcus pneumoniae with dihydroneopterin aldolase and hydroxymethyldihydropterin pyrophosphokinase activities.

  Lopez P., Lacks S.A.

  A protein encoded by sulD, one of four genes in a previously cloned folate biosynthetic operon of Streptococcus pneumoniae, had been shown to harbor 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase activity. This SulD protein was purified and shown now to harbor also dihydroneopterin aldolase a ... >> More

  A protein encoded by sulD, one of four genes in a previously cloned folate biosynthetic operon of Streptococcus pneumoniae, had been shown to harbor 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase activity. This SulD protein was purified and shown now to harbor also dihydroneopterin aldolase activity. The bifunctional protein therefore catalyzes two successive steps in folate biosynthesis. The aldolase activity can be ascribed to the N-terminal domain of the SulD polypeptide, and the pyrophosphokinase activity can be ascribed to the C-terminal domain. Homologs of the dihydroneopterin aldolase domain were identified in other species, in one of which the domain was encoded as a separate polypeptide. The native SulD protein is a trimer or tetramer of a 31-kDa subunit, and it dissociated reversibly after purification. Dihydroneopterin aldolase activity required the multimeric protein, whereas pyrophosphokinase was expressed by the monomeric form. With purified SulD, the amount of 6-hydroxymethyl-7,8-dihydropterin product formed by the aldolase was proportional to the fourth power of the enzyme concentration, as expected for a reversibly dissociating tetramer. By identifying the gene encoding dihydroneopterin aldolase, this work extends our understanding of the molecular basis of the folate biosynthetic system common to many organisms. << Less

  J. Bacteriol. 175:2214-2220(1993) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• DNA sequence of folate biosynthesis gene sulD, encoding hydroxymethyldihydropterin pyrophosphokinase in Streptococcus pneumoniae, and characterization of the enzyme.

  Lopez P., Greenberg B., Lacks S.A.

  A cloned segment of the chromosome of Streptococcus pneumoniae, in which mutations to sulfonamide resistance occur, contains several genes encoding enzymes for folate biosynthesis. Determination of the DNA sequence of parts of this segment and identification of a putative promoter and terminator o ... >> More

  A cloned segment of the chromosome of Streptococcus pneumoniae, in which mutations to sulfonamide resistance occur, contains several genes encoding enzymes for folate biosynthesis. Determination of the DNA sequence of parts of this segment and identification of a putative promoter and terminator of transcription indicate an operon composed of four genes. The first, sulA, encodes the enzyme dihydropteroate synthase. The functions of the second and third possible genes, sulB and sulC, are not known. The last gene, sulD, encodes a 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase. The product of this enzyme is the substrate for dihydropteroate synthetase. The enzyme protein was partially purified and shown to consist of a single subunit of 31 kilodaltons, encoded by sulD. On the basis of gel filtration behavior, the native protein appears to be a trimer or tetramer. Subcloning of the sulD gene in an Escherichia coli expression vector increased expression of the pyrophosphokinase 1,000-fold over the level produced by a single copy of the chromosomal gene. << Less

  J. Bacteriol. 172:4766-4774(1990) [PubMed] [EuropePMC]

• Characterization of the Saccharomyces cerevisiae Fol1 protein: starvation for C1 carrier induces pseudohyphal growth.

  Gueldener U., Koehler G.J., Haussmann C., Bacher A., Kricke J., Becher D., Hegemann J.H.

  Tetrahydrofolate (vitamin B9) and its folate derivatives are essential cofactors in one-carbon (C1) transfer reactions and absolutely required for the synthesis of a variety of different compounds including methionine and purines. Most plants, microbial eukaryotes, and prokaryotes synthesize folat ... >> More

  Tetrahydrofolate (vitamin B9) and its folate derivatives are essential cofactors in one-carbon (C1) transfer reactions and absolutely required for the synthesis of a variety of different compounds including methionine and purines. Most plants, microbial eukaryotes, and prokaryotes synthesize folate de novo. We have characterized an important enzyme in this pathway, the Saccharomyces cerevisiae FOL1 gene. Expression of the budding yeast gene FOL1 in Escherichia coli identified the folate biosynthetic enzyme activities dihydroneopterin aldolase (DHNA), 7,8-dihydro-6-hydroxymethylpterin-pyrophosphokinase (HPPK), and dihydropteroate synthase (DHPS). All three enzyme activities were also detected in wild-type yeast strains, whereas fol1Delta deletion strains only showed background activities, thus demonstrating that Fol1p catalyzes three sequential steps of the tetrahydrofolate biosynthetic pathway and thus is the central enzyme of this pathway, which starting from GTP consists of seven enzymatic reactions in total. Fol1p is exclusively localized to mitochondria as shown by fluorescence microscopy and immune electronmicroscopy. FOL1 is an essential gene and the nongrowth phenotype of the fol1 deletion leads to a recessive auxotrophy for folinic acid (5'-formyltetrahydrofolate). Growth of the fol1Delta deletion strain on folinic acid-supplemented rich media induced a dimorphic switch with haploid invasive and filamentous pseudohyphal growth in the presence of glucose and ammonium, which are known suppressors of filamentous and invasive growth. The invasive growth phenotype induced by the depletion of C1 carrier is dependent on the transcription factor Ste12p and the flocullin/adhesin Flo11p, whereas the filamentation phenotype is independent of Ste12p, Tec1p, Phd1p, and Flo11p, suggesting other signaling pathways as well as other adhesion proteins. << Less

  Mol. Biol. Cell 15:3811-3828(2004) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.