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Isolation, nucleotide sequence, and physiological relevance of the gene encoding triose phosphate isomerase from Kluyveromyces lactis.

Lack of triose phosphate isomerase activity (TIM) is of special interest because this enzyme works at an important branch point of glycolytic flux. In this paper, we report the cloning and sequencing of the Kluyveromyces lactis gene encoding TIM. Unlike Saccharomyces cerevisiae DeltaTPI1 mutants, the K. lactis mutant strain was found to be able to grow on glucose. Preliminary bioconversion experiments indicated that, like the S. cerevisiae TIM-deficient strain, the K. lactis TIM-deficient strain is able to produce glycerol with high yield.

Blotting, Southern↗

The tigA gene is a transcriptional fusion of glycolytic genes encoding triose-phosphate isomerase and glyceraldehyde-3-phosphate dehydrogenase in oomycota.

Genes encoding triose-phosphate isomerase (TPI) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) are fused and form a single transcriptional unit (tigA) in Phytophthora species, members of the order Pythiales in the phylum Oomycota. This is the first demonstration of glycolytic gene fusion in eukaryotes and the first case of a TPI-GAPDH fusion in any organism. The tigA gene from Phytophthora infestans has a typical Oomycota transcriptional start point consensus sequence and, in common with most Phytophthora genes, has no introns. Furthermore, Southern and PCR analyses suggest that the same organization exists in other closely related genera, such as Pythium, from the same order (Oomycota), as well as more distantly related genera, Saprolegnia and Achlya, in the order Saprolegniales. Evidence is provided that in P. infestans, there is at least one other discrete copy of a GAPDH-encoding gene but not of a TPI-encoding gene. Finally, a phylogenetic analysis of TPI does not place Phytophthora within the assemblage of crown eukaryotes and suggests TPI may not be particularly useful for resolving relationships among major eukaryotic groups.

Amino Acid Sequence↗

Multiplex PCR targeting tpi (triose phosphate isomerase), tcdA (Toxin A), and tcdB (Toxin B) genes for toxigenic culture of Clostridium difficile.

A multiplex PCR toxigenic culture approach was designed for simultaneous identification and toxigenic type characterization of Clostridium difficile isolates. Three pairs of primers were designed for the amplification of (i) a species-specific internal fragment of the tpi (triose phosphate isomerase) gene, (ii) an internal fragment of the tcdB (toxin B) gene, and (iii) an internal fragment of the tcdA (toxin A) gene allowing distinction between toxin A-positive, toxin B-positive (A+B+) strains and toxin A-negative, toxin B-positive (A-B+) variant strains. The reliability of the multiplex PCR was established by using a panel of 72 C. difficile strains including A+B+, A-B-, and A-B+ toxigenic types and 11 other Clostridium species type strains. The multiplex PCR assay was then included in a toxigenic culture approach for the detection, identification, and toxigenic type characterization of C. difficile in 1,343 consecutive human and animal stool samples. Overall, 111 (15.4%) of 721 human samples were positive for C. difficile; 67 (60.4%) of these samples contained A+B+ toxigenic isolates, and none of them contained A-B+ variant strains. Fifty (8%) of 622 animal samples contained C. difficile strains, which were toxigenic in 27 (54%) cases, including 1 A-B+ variant isolate. Eighty of the 721 human stool samples (37 positive and 43 negative for C. difficile culture) were comparatively tested by Premier Toxins A&B (Meridian Bioscience) and Triage C. difficile Panel (Biosite) immunoassays, the results of which were found concordant with toxigenic culture for 82.5 and 92.5% of the samples, respectively. The multiplex PCR toxigenic culture scheme described here allows combined diagnosis and toxigenic type characterization for human and animal C. difficile intestinal infections.

Animals↗

Recent amplification of triose phosphate isomerase related sequences in lettuce.

A random cDNA clone was identified as distinguishing near-isogenic lines for downy mildew resistance in lettuce. The clone detected multiple restriction fragments in genomic Southern blots of lettuce. Restriction fragment length polymorphisms (RFLPs) detected by this clone mapped to separate clusters of resistance genes; therefore, these sequences were studied in a greater detail. Sequence analysis indicated that the cDNA encoded the glycolytic enzyme triose phosphate isomerase (TPI). The lettuce clone shares 85% sequence similarity at the amino acid level with TPI from maize. TPI-related sequences were mapped in lettuce using three crosses. Ten loci were distributed in six linkage groups. Possible mechanisms of amplification and dispersion were investigated. Retrotransposition was excluded, since intron five is retained in all TPI-related genomic sequences. Large scale chromosomal rearrangements were not involved, as RFLP markers flanking TPI loci were not duplicated. A high level of genomic variability was detected by the TPI clone; 37 different restriction fragments were detected in Southern hybridizations to 64 populations of lettuce including 47 cultivars of Lactuca sativa and five wild species. Species distantly related to L. sativa had few TPI loci, indicating that their amplification and dispersion were recent and had occurred after the emergence of the L. serriola complex.

Amino Acid Sequence↗

Triose phosphate isomerase of Stellaria longipes (Caryophyllaceae).

A cDNA encoding triose phosphate isomerase (TPI) of Stellaria longipes has been isolated and sequenced. The TPI of S. longipes exhibits high similarity to the TPIs from other species at both the nucleotide and amino acid levels. Southern blot analysis showed that the S. longipes genome contained multiple TPI-like nucleotide sequences and only a low degree of polymorphism was observed among genotypes of different habitats. The levels of TPI mRNA, detected by hybridization to the TPI cDNA, appeared similar between the genotypes. However, different genotypes showed variations in the total TPI activity, reflecting the possible ecological effect on the TPI gene expression. Northern blot hybridization to the cDNA also indicated a higher level of TPI mRNA in leaves than in roots, suggesting tissue-specific expression of TPI gene(s). Phylogenetic analysis of the TPI amino acid sequences from 16 taxa suggested that the TPI from S. longipes was more closely related to cytosolic TPIs from other plants than it was to TPIs from prokaryotes.

Amino Acid Sequence↗

Subunit interactions and catalytic activity of triose phosphate isomerase.

Rabbit and chicken triose phosphate isomerase were labelled with iodo-(1-14C)-acetamide. The efficiencies of renaturation after denaturation in guanidinium chloride were similar to those of the unlabelled enzymes. The enzymes were immobilised to Sepharose 4B and after guanidinium treatment only immobilised monomers remained on the gel. Hybridisation studies demonstrated that the dimeric form could be reformed on the denatured gels with recovery of the original specific activity. Under similar conditions formation of rabbit-chicken dimers were observed. However, competition studies demonstrated a preferential formation of the homogeneous dimers.

Animals↗

Residual triose phosphate isomerase activity and color measurements to determine adequate cooking of ground beef patties.

The objectives were to (i) compare the use of triose phosphate isomerase (TPI) activity and internal color scores for determination of cooking adequacy of beef patties and (ii) determine the effect of frozen storage and fat content on residual TPI activity in ground beef. Ground beef patties (24.4% fat) were cooked to five temperatures ranging from 60.0 to 82.2 degrees C. TPI activity decreased as beef patty cooking temperature was increased from 60.0 to 71.1 degrees C; however, no difference (P > 0.05) in activity (6.3 U/kg meat) was observed in patties cooked to 71.1 degrees C and above. Degree of doneness color scores, a* values and b* values, of ground beef patties decreased as internal temperature was increased from 60.0 to 71.1 degrees C; however, temperature had no effect on L* values. TPI activity in raw ground beef after five freeze-thaw cycles did not differ from the control. Three freeze-thaw cycles of raw ground beef resulted in a 57.2% decrease in TPI activity after cooking. TPI activity of cooked beef increased during 2 months of frozen storage, but TPI activity in ground beef stored for 3 months or longer did not differ from the unfrozen control. While past research has shown color to be a poor indicator of adequate thermal processing, our results suggest that undercooked ground beef patties could be distinguished from those that had been adequately cooked following U.S. Department of Agriculture guidelines using residual TPI activity as a marker.

Animals↗

Gene cloning and amino acid sequence analysis of triose-phosphate isomerase of Schistosoma japonicum Chinese strain.

A pair of primers was synthesized according to the DNA sequence of Schistosoma japonicum Philippine strain, and the mRNA of adult worms of S. japonicum Chinese strain was prepared. The gene of triose-phosphate isomerase of S. japonicum Chinese strain (SjC TPI) was successfully cloned from the mRNA through reverse transcription polymerase chain reaction (RT-PCR) technic with the primers. The DNA sequence of the gene showed that the open reading frame of encoding SjC TPI DNA includes 759bp, which has 84% homology to Sm TPI, 99.7% homology to SjP TPI. The analysis of deduced amino acid sequence of SjC TPI indicates that SjC TPI is 84.9% (214/252) identical with Sm TPI and 99.2% (250/252) with SjP TPI. The peptide-structure analysis presents 7 extra-surface, hydrophilic regions in the molecule of SjC TPI, the molecular weight of SjC TPI is 27,619. The isoelectric point is 7.38.

Amino Acid Sequence↗

Triose phosphate isomerase deficiency in 3 French families: two novel null alleles, a frameshift mutation (TPI Alfortville) and an alteration in the initiation codon (TPI Paris).

Three French families with triose phosphate isomerase (TPI) deficiency were studied, and 2 new mutations giving rise to null alleles were observed: a frameshift mutation with deletion of the 86-87 TG dinucleotide in codon 29 (TPI Alfortville) and a T-->A transversion in nucleotide 2 of the initiation codon (TPI Paris). The first mutation occurred in compound heterozygosity with the frequent E105D mutation. The second mutation occurred in association with the 2-nucleotide promoter variant (-43G,-46A). In a third family, the propositus was an E105D homozygote. In the TPI Paris family, the coinheritance of the -43,-46 promoter variant appeared to exert little, if any, effect on TPI enzyme activity, a finding consistent with 2 previous reports that questioned the putative role of the promoter polymorphism as a true deficiency variant. Similarly, the further coinheritance of glucose-6-phosphate dehydrogenase (G6PD) A- (202 G-->A/376 A-->G) appeared to have little effect on the observed phenotype. Compound heterozygosity for the E105D mutation with the null allele TPI Alfortville appeared to lead to a more severe clinical syndrome than did E105D homozygosity, suggesting that compound heterozygosity with null alleles may lead to more profound clinical abnormalities than homozygosity with missense alleles. A simple, rapid polymerase chain reaction and restriction enzyme procedure for the E105D mutation was developed for prenatal diagnosis in one family and subsequently used for screening in the other families.

Adult↗

DNA sequence analysis of the triose phosphate isomerase gene from isolates of Giardia lamblia.

OBJECTIVE: To confirm the genetic relation between Giardia lamblia (G. lamblia) isolates from different geographic regions of China and other countries. METHODS: Genomic DNA were extracted from the trophozoites or cysts of Giardia lamblia. The triose phosphate isomerase (tim) gene was amplified using polymerase chain reaction (PCR) technique. PCR products were digested with endonuclease and sequenced. The data of sequencing were analyzed with the DNAstar software and compared with that of the isolates acquired from GenBank. RESULTS: Of nine isolates of Giardia lamblia from China (C1, C2, CH2 and CH3), Cambodia (CAM), Australia (A1 and A2) and America (BP and CDC), respectively, 3 (A1, A2 and CAM) fit into Group 1 (WB), 2 (CH2 and CH3)) into Group 2, and 4 (C1, C2, BP and CDC) into Group 3 (GS). The results confirmed the genetic relatedness of G. lamblia isolates from all over the world. CONCLUSION: Genotyping isolates of G. Lamblia provides important information for establishing the phylogenetic relationship or for the epidemiological evaluation of the spreading of this organism.

Amino Acid Sequence↗

[A case of congenital non-spherocytic hemolytic anemia caused by triose phosphate isomerase deficiency. Prenatal diagnosis].

Prenatal diagnosis: The authors present a personal case of triose-phosphate-isomerase deficiency. Clinically the deficiency associates a constitutional non spherocytic anemia, paroxystic and precocius, and neuromuscular symptoms (axial hypotonia and limb palsies). A diaphragmatic paralysis may complicate the syndrome. Infections are frequent. Survival rarely goes beyond 5 years of age. Biochemical exams show the ubiquity of the deficiency. The physiopathology remains obscure. The TPI deficiency is heritable (autosomal recessive transmission). The gene has been mapped on the short arm of the chromosome 12. Prenatal diagnosis is possible.

Anemia, Hemolytic, Congenital↗

T and B epitope determination and analysis of multiple antigenic peptides for the Schistosoma mansoni experimental vaccine triose-phosphate isomerase.

Schistosoma mansoni triose-phosphate isomerase (TPI), a glycolytic enzyme, was originally identified as the target of the mAb M.1 that conferred protection when the antibody was administered in vivo. In this study we increase the evidence that schistosome TPI is a potential vaccine Ag by showing that it also a potent inducer of IL-2 and IFN-gamma production (Th1 responses), driving production of these cytokines in the same cell populations of infected animals that have high Th2 responses directed at other parasite egg Ag. With the goal of synthetic peptide vaccine design, rTPI was used to determine specific T and B cell epitopes recognized by two strains of mice representing high and moderate responders (C57Bl/6J and CBA/J). All selected epitopes were from nonconserved regions of TPI and thus parasite-specific. We then defined minimal size immunoreactive epitopes and synthesized four-armed multiple antigenic peptides (MAP) consisting of T and B cell epitopes that could be recognized by both strains of mice in the same molecule. Characterization of the immunoreactivity of the MAP showed that higher antibody recognition of the MAP was attained when the B cell epitope was placed on the amino termini relative to the T cell epitope, whereas equivalent immunoreactivity occurred for the T cell epitopes when located at either position. Most interesting was the finding that one of the minimal T cell epitopes, when incorporated into the MAP, required enlarging to retain immunoreactivity. Finally we showed that both the full-length TPI molecule and the final version of the MAP were immunogenic to T cells in naive animals and induced cross-recognition in the form of IL-2 and IFN-gamma production.

Amino Acid Sequence↗

The hinged lid of yeast triose-phosphate isomerase. Determination of the energy barrier between the two conformations.

Covalent modification of Glu165 in the catalytic center of triose-phosphate isomerase with the substrate analogue 3-chloroacetol phosphate traps the complex in two conformations. The two resulting 31P NMR resonances at 6.9 and 5.7 ppm appear to reflect conformations in which the hinged lid (residues 167-176) is in the open and closed positions. The conformation represented by the 5.7-ppm resonance is more stable, and unfolding and refolding in guanidine converts all of the molecules to the 5.7-ppm conformation. The complete conformational transition from 6.9 to 5.7 ppm also takes place as a function of time and temperature. Under these conditions the native enzyme retains more than 80% of the catalytic activity, indicating that this conversion is not due to thermal denaturation of the enzyme. Circular dichroic and fluorescence spectroscopy indicate that the 3-chloroacetol phosphate-modified enzyme does not undergo major structural changes. From the temperature dependence of this transition, an energy barrier of 144 kJ/mol (34.4 kcal/mol) was calculated for this conversion.

Amino Acid Sequence↗

Effects of AMP and fructose 2,6-bisphosphate on fluxes between glucose 6-phosphate and triose-phosphate in renal cortical extracts.

Gluconeogenic flux exceeds glycolytic flux at the hexose-phosphate steps when measured in extracts of kidney cortex from well-fed rats. Addition of AMP and/or fructose 2,6-bisphosphate to the assay medium partially eradicates the difference. Using principles developed by Kacser, H., and Burns, J. A. ((1973) in Rate Control of Biological Processes (Davies, D. D., ed) pp. 65-104, Cambridge University Press, London) and Heinrich R., and Rapoport T. A. ((1974) Eur. J. Biochem. 42, 97-105), flux control coefficients of enzymes participating in the pathway segments from glucose 6-phosphate to triose-phosphates and from glycerol 3-phosphate to glucose 6-phosphate were determined by additions of the respective enzyme to the system. Results show that the flux control coefficients are highly modulated by the presence of allosteric effectors, as might be expected according to the regulatory properties of phosphofructokinase and fructose-1,6-bisphosphatase purified from this origin. Measured reductions of fructose 2,6-bisphosphate and AMP levels during acidosis, starvation, or after phenylephrine treatment suggest that these changes contribute to enhanced gluconeogenesis under these conditions.

Adenosine Monophosphate↗

Species dependence of enzyme-substrate encounter rates for triose phosphate isomerases.

Triose phosphate isomerase (TIM) is a diffusion-controlled enzyme whose rate is limited by the diffusional encounter of the negatively charged substrate glyceraldehyde 3-phosphate (GAP) with the homodimeric enzyme's active sites. Translational and orientational steering of GAP toward the active sites by the electrostatic field of chicken muscle TIM has been observed in previous Brownian dynamics (BD) simulations. Here we report simulations of the association of GAP with TIMs from four species with net charges at pH 7 varying from -12e to +12e. Computed second-order rate constants are in good agreement with experimental data. The BD simulations and computation of average Boltzmann factors of substrate-protein interaction energies show that the protein electrostatic potential enhances the rates for all the enzymes. There is much less variation in the computed rates than might be expected on the basis of the net charges. Comparison of the electrostatic potentials by means of similarity indices shows that this is due to conservation of the local electrostatic potentials around the active sites which are the primary determinants of electrostatic steering of the substrate.

Animals↗

Expression of the triose phosphate translocator gene from potato is light dependent and restricted to green tissues.

The export of primary photosynthesis products from chloroplasts into the cytoplasm is mediated by the triose phosphate translocator. The transporter is an integral membrane protein localized at the inner envelope of chloroplasts. In order to study the expression of the major chloroplast envelope protein gene E29, which is assumed to function as the translocator, we have isolated corresponding cDNA clones from potato. A full-length clone was sequenced and shown to be highly homologous to the E29 gene from spinach. Expression on the RNA level is restricted to green tissues, is light dependent and cannot be induced by sucrose in darkness. The presence of a single-copy gene argues for the existence of different translocator systems responsible for import and export of carbohydrates in chloroplasts and amyloplasts.

Amino Acid Sequence↗

Enzymic synthesis of lacto-N-triose II and its positional analogues.

N-acetylhexosaminidase from Nocardia orientalis catalysed the synthesis of lacto-N-triose II glycoside (beta-D-GlcNAc-(1-3)-beta-D-Gal-(1-4)-beta-D-Glc-OMe, 3) with its isomers beta-D-GlcNAc-(1-6)-beta-D-Gal-(1-4)-beta-d-Glc-OMe (4) and beta-D-Gal-(1-4)-[beta-D-GlcNAc-(1-6)]-beta-D-Glc-OMe (5) through N-acetylglucosaminyl transfer from N,N'-diacetylchitobiose (GlcNAc2) to methyl beta-lactoside. The enzyme formed the mixture of trisaccharides 3, 4 and 5 in 17% overall yield based on GlcNAc2, in a ratio of 20:21:59. With p-nitrophenyl beta-lactoside as an acceptor, the enzyme also produced p-nitrophenyl beta-lacto-N-trioside II (beta-D-GlcNAc-(1-3)-beta-D-Gal-(1-4)-beta-D-Glc-OC6H4NO2-p, 6) with its isomers beta-D-GlcNAc-(1-6)-beta-D-Gal-(1-4)-beta-D-Glc-OC6H4NO2-p (7) and beta-D-Gal-(1-4)-[beta-D-GlcNAc-(1-6)]-beta-D-Glc-OC6H4NO2-p (8). In this case, when an inclusion complex of p-nitrophenyl lactoside acceptor with beta-cyclodextrin was used the regioselectivity of glycosidase-catalysed formation of trisaccharide glycoside was substantially changed. It resulted not only in a significant increase of the overall yield of transfer products, but also in the proportion of the desired compound 6.

Carbohydrate Conformation↗

Compensation of decreased triose phosphate/phosphate translocator activity by accelerated starch turnover and glucose transport in transgenic tobacco.

Tobacco (Nicotiana tabacum L.) plants were transformed with an antisense construct of the chloroplast triose phosphate/phosphate translocator (TPT). Three transformant lines of the T4 progeny, which showed a large decrease in the transcript level of the TPT were used for further biochemical and physiological characterisation. In all antisense lines tested, TPT transport activity was diminished by 50-70% compared with the wild type (WT). Despite this high reduction in the transport capacity, alpha TPT plants lacked any visible phenotype. Hexokinase and alpha-amylase activities were increased in alpha TPT plants compared with the WT, whereas activities of ribulose-1,5-bisphosphate carboxylase/oxygenase and ADP-glucose pyrophosphorylase (AGPase) were not affected. At the end of a 14-h light period, leaf starch contents in alpha TPT lines were similar to those of the WT and controls, indicating that a decrease in the TPT had no effect on starch accumulation. Sucrose contents were diminished by more than 50% in alpha TPT lines compared with control plants. The time course of starch accumulation revealed a transient increase in the starch content in a selected alpha TPT line after 6 h in the light, followed by a decrease towards the end of the light period. Labelling with 14C indicated that during the dark and light (late afternoon) periods starch is mobilised at higher rates in alpha TPT lines than in the controls. Glucose/fructose ratios at the end of the dark period were increased from 1.2 in control plants to 2 in alpha TPT lines indicating increased amylolytic starch degradation. Initial rates of [14C] glucose transport in isolated chloroplasts were increased by a factor of 2-3 in alpha TPT plants compared with the WT. Rates of CO2 assimilation were substantially diminished in the alpha TPT lines in high CO2 and low O2, but remained unaffected in ambient CO2. The rate of photosynthetic electron transport during the induction of photosynthesis in saturating CO2 exhibited pronounced oscillations only in WT and control plants. Oscillations were less pronounced in alpha TPT plants, indicating that phosphate limitation of photosynthesis is lowered in alpha TPT plants compared with the WT. It is proposed that photoassimilates are more readily directed into starch biosynthesis in alpha TPT plants. This is supported by determinations of 3-phosphoglycerate levels (an activator of AGPase) during the transition from dark to light in high CO2.

Amino Acids↗