Publications

• Moonlighting glutamate formiminotransferases can functionally replace 5-formyltetrahydrofolate cycloligase.

  Jeanguenin L., Lara-Nunez A., Pribat A., Mageroy M.H., Gregory J.F. III, Rice K.C., de Crecy-Lagard V., Hanson A.D.

  5-Formyltetrahydrofolate (5-CHO-THF) is formed by a side reaction of serine hydroxymethyltransferase. Unlike other folates, it is not a one-carbon donor but a potent inhibitor of folate enzymes and must therefore be metabolized. Only 5-CHO-THF cycloligase (5-FCL) is generally considered to do this ... >> More

  5-Formyltetrahydrofolate (5-CHO-THF) is formed by a side reaction of serine hydroxymethyltransferase. Unlike other folates, it is not a one-carbon donor but a potent inhibitor of folate enzymes and must therefore be metabolized. Only 5-CHO-THF cycloligase (5-FCL) is generally considered to do this. However, comparative genomic analysis indicated (i) that certain prokaryotes lack 5-FCL, implying that they have an alternative 5-CHO-THF-metabolizing enzyme, and (ii) that the histidine breakdown enzyme glutamate formiminotransferase (FT) might moonlight in this role. A functional complementation assay for 5-CHO-THF metabolism was developed in Escherichia coli, based on deleting the gene encoding 5-FCL (ygfA). The deletion mutant accumulated 5-CHO-THF and, with glycine as sole nitrogen source, showed a growth defect; both phenotypes were complemented by bacterial or archaeal genes encoding FT. Furthermore, utilization of supplied 5-CHO-THF by Streptococcus pyogenes was shown to require expression of the native FT. Recombinant bacterial and archaeal FTs catalyzed formyl transfer from 5-CHO-THF to glutamate, with k(cat) values of 0.1-1.2 min(-1) and K(m) values for 5-CHO-THF and glutamate of 0.4-5 μM and 0.03-1 mM, respectively. Although the formyltransferase activities of these proteins were far lower than their formiminotransferase activities, the K(m) values for both substrates relative to their intracellular levels in prokaryotes are consistent with significant in vivo flux through the formyltransferase reaction. Collectively, these data indicate that FTs functionally replace 5-FCL in certain prokaryotes. << Less

  J. Biol. Chem. 285:41557-41566(2010) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• The nucleotide sequence of porcine formiminotransferase cyclodeaminase. Expression and purification from Escherichia coli.

  Murley L.L., Mejia N.R., Mackenzie R.E.

  We have isolated and characterized cDNA clones encoding the porcine liver octameric enzyme, 5-formiminotetrahydrofolate:L-glutamate N-formiminotransferase (EC 2.1.2.5)-formiminotetrahydrofolate cyclodeaminase (EC 4.3.1.4). The cDNA encodes a novel amino acid sequence of 541 residues which contains ... >> More

  We have isolated and characterized cDNA clones encoding the porcine liver octameric enzyme, 5-formiminotetrahydrofolate:L-glutamate N-formiminotransferase (EC 2.1.2.5)-formiminotetrahydrofolate cyclodeaminase (EC 4.3.1.4). The cDNA encodes a novel amino acid sequence of 541 residues which contains exact matches to two sequences derived by automated sequence analysis of CNBr cleavage fragments isolated from the porcine enzyme. The recombinant enzyme has been expressed as a soluble protein in Escherichia coli at levels 4-fold higher than those observed in liver, and is bifunctional, displaying both transferase and deaminase activities. With a calculated subunit molecular mass of 58,926 Da, it is similar in size to the enzyme isolated from porcine liver. Purification of the enzyme from E. coli involves chromatography on a novel polyglutamate column which might interact with the folylpolyglutamate binding site of the protein. The purified recombinant enzyme has a transferase specific activity of 39-41 units/mg/min. << Less

  J. Biol. Chem. 268:22820-22824(1993) [PubMed] [EuropePMC]

• The molecular basis of glutamate formiminotransferase deficiency.

  Hilton J.F., Christensen K.E., Watkins D., Raby B.A., Renaud Y., De La Luna S., Estivill X., MacKenzie R.E., Hudson T.J., Rosenblatt D.S.

  Glutamate formiminotransferase deficiency, an autosomal recessive disorder and the second most common inborn error of folate metabolism, is presumed to be due to defects in the bifunctional enzyme glutamate formiminotransferase-cyclodeaminase (FTCD). Features of a severe phenotype, first identifie ... >> More

  Glutamate formiminotransferase deficiency, an autosomal recessive disorder and the second most common inborn error of folate metabolism, is presumed to be due to defects in the bifunctional enzyme glutamate formiminotransferase-cyclodeaminase (FTCD). Features of a severe phenotype, first identified in patients of Japanese descent, include elevated levels of formiminoglutamate (FIGLU) in the urine in response to histidine administration, megaloblastic anemia, and mental retardation. Features of a mild phenotype include high urinary excretion of FIGLU in the absence of histidine administration, mild developmental delay, and no hematological abnormalities. We found mutations in the human FTCD gene in three patients with putative glutamate formiminotransferase deficiency. Two siblings were heterozygous for missense mutations, c.457C>T (R135C) and c.940G>C (R299P). Mutagenesis of porcine FTCD and expression in E. coli showed that the R135C mutation reduced formiminotransferase activity to 61% of wild-type, whereas the R299P mutation reduced this activity to 57% of wild-type. The third patient was hemizygous for c.1033insG, with quantitative PCR indicating that the other allele contained a deletion. These mutations are the first identified in glutamate formiminotransferase deficiency and demonstrate that mutations in FTCD represent the molecular basis for the mild phenotype of this disease. << Less

  Hum. Mutat. 22:67-73(2003) [PubMed] [EuropePMC]

• Cloning and characterization of human FTCD on 21q22.3, a candidate gene for glutamate formiminotransferase deficiency.

  Solans A., Estivill X., de la Luna S.

  We have identified a new human gene, FTCD, which maps to chromosome 21q22.3 and encodes the enzyme formiminotransferase cyclodeaminase, an intermediate metabolism enzyme that links histidine catabolism to folate metabolism. The major cDNA encodes a protein containing 541 amino acid residues and sh ... >> More

  We have identified a new human gene, FTCD, which maps to chromosome 21q22.3 and encodes the enzyme formiminotransferase cyclodeaminase, an intermediate metabolism enzyme that links histidine catabolism to folate metabolism. The major cDNA encodes a protein containing 541 amino acid residues and shows 84% identity with porcine FTCD. Several other cDNAs have been isolated, which may result from alternative splicing events and have the potential to code for three different protein isoforms. The gene is highly expressed in human fetal and adult liver. The two FTCD protein domains show high sequence similarity to two distinct open reading frames from eubacterial genomes, suggesting that eukaryotic FTCD appeared through a gene fusion event. Defects in the glutamate formiminotransferase pathway have been documented, and the deficiency is presumed to be inherited as an autosomal recessive trait. The sequence reported here may be helpful in identifying the primary defect in glutamate formiminotransferase deficiency and establishing a molecular diagnosis. << Less

  Cytogenet. Cell Genet. 88:43-49(2000) [PubMed] [EuropePMC]