The de-repression of thiamine biosynthesis by adenosine a tool for investigating this biosynthetic pathway

Newell, P. C.; Tucker, R. G.

doi:10.1042/bj1000512

Cited by 33 publications

(19 citation statements)

References 14 publications

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“…The stimulation of thiamine synthesis by resting cells of S. typhimurium preincubated with adenosine was also reported (10). As shown in Table 8, it was found that phenylalanine (5mM) increased the thiamine synthesizing activities from hydroxy methylpyrimidine and thiazole about twice as much as that of the non-supplemented.…”

Section: Thiaminesupporting

confidence: 54%

“…However, these active compounds except for sulfur-containing amino acids had no appreciable stimulatory effects on de novo synthesis of thiamine in growing, or resting cells of E. coli (8). This finding is well understandable from the observations that thiamine biosynthesis is regulated by repression-derepression mechanism in Aerobacter aerogenes (9), in Salmonella typhimurium (10) and E . coli (14).…”

mentioning

confidence: 71%

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Effect of Amino Acids and Purine Bases on Thiamine Synthesis by Escherichia coli

et al. 1968

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Phenylalanine and histidine, out of several amino acids tested by the addition to the growth medium of Escherichia coli, showed stimulatory effects on thiamine production y the cells. In order to know the mechanism of phenylalanine action, it was compared with the adenine effect in which adenine added to the growth medium caused a decrease in thiamine production of E. coli accom panying with the increase of thiamine synthesizing activity from hydroxymethylpyrimidine and thiazole. Phenylalanine had also a similar elevating effect on thiamine synthesizing activity from hy droxymethylpyrimidine and thiazole in spite of the increase in cel lular thiamine contents. The phenylalanine effect could be abolished by a simultaneous thiazole addition at a physiological concentra tion for the organism in contrast with the adenine effect, which was arrested by hydroxymethylpyrimidine addition. The phenyl alanine effect is supposed to be concerned with the synthesis of thiazole moiety of thiamine. The regulation of thiamine biosyn thesis in E. coli was also discussed.

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Section: Thiaminesupporting

confidence: 54%

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confidence: 71%

Effect of Amino Acids and Purine Bases on Thiamine Synthesis by Escherichia coli

et al. 1968

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“…The position of AICAR in the purine pathway indicated its effect on thiamine synthesis was indirect. Past workers suggested that the site of this effect was PurF, which was shown to be inhibited allosterically by a number of purine nucleotides (32,35,36). In vitro studies with purified PurF (33,52,59) have not directly addressed an allosteric role for AICAR (H. Zalkin, personal communication).…”

Section: Thimentioning

confidence: 99%

Metabolic Flux in Both the Purine Mononucleotide and Histidine Biosynthetic Pathways Can Influence Synthesis of the Hydroxymethyl Pyrimidine Moiety of Thiamine in Salmonella enterica

2002

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Together, the biosyntheses of histidine, purines, and thiamine pyrophosphate (TPP) contain examples of convergent, divergent, and regulatory pathway integration. Mutations in two purine biosynthetic genes (purI and purH) affect TPP biosynthesis due to flux through the purine and histidine pathways. The molecular genetic characterization of purI mutants and their respective pseudorevertants resulted in the conclusion that <1% of the wild-type activity of the PurI enzyme was sufficient for thiamine but not for purine synthesis. The respective pseudorevertants were found to be informational suppressors. In addition, it was shown that accumulation of the purine intermediate aminoimidazole carboxamide ribotide inhibits thiamine synthesis, specifically affecting the conversion of aminoimidazole ribotide to hydroxymethyl pyrimidine.Cellular metabolism requires the control of flux through a complex network of pathways. This control is accomplished by regulation at several levels. Regulation of gene transcription or mRNA translation can control individual pathways. Allosteric control of the enzyme catalyzing the first committed step of a pathway is another mechanism used by cells to regulate biosynthetic pathways. Regulatory effects resulting from interactions between pathways are less well understood, despite the fact that many metabolites are present in multiple pathways in the cell.The expanding network of defined pathways that affect the biosynthesis of thiamine provides an attractive model system to investigate metabolic integration. As depicted in Fig. 1, the biosynthetic pathway for the hydroxymethylpyrimidine (HMP) moiety of thiamine pyrophosphate (TPP) branches off from that for purine mononucleotides at the metabolite aminoimidazole ribotide (AIR). Relevant to the work presented here is a subsequent purine intermediate, aminoimidazole carboxamide ribotide (AICAR), that is also a by-product of the biosynthesis of histidine.The distribution of AIR at the purine-HMP branch point must account for the different level of purine mononucleotides and TPP required for growth (purines/TPP ratio, 1,000:1, based on auxotrophic requirements). The distribution of AIR between these pathways could be accomplished by kinetic parameters of the relevant enzymes; however, the first dedicated HMP biosynthetic enzyme is poorly understood, thus hampering direct tests of this possibility.While thiamine and purine mononucleotides are synthesized by pathways diverging at the metabolite AIR, the cellular pool of AICAR arises from both purine and histidine biosynthesis and is used exclusively for purine mononucleotide synthesis (28, 29). Since AICAR enters purine mononucleotide synthesis after the purine-HMP branch point, no interaction between AICAR and HMP synthesis was anticipated. Hence, it was surprising to find that mutants blocked in the utilization of AICAR (purH mutants) required both purines and thiamine to grow (16, 58). The hypothesis proposed to explain this requirement posited that inactivation of purH would result in the acc...

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“…In most bacteria, the first five enzymes used to generate HMP-PP are shared with the purine biosynthetic pathway (25,26). The formation of the first common intermediate, phosphoribosyl amine (PRA), is catalyzed by PurF (phosphoribosylpyrophosphate amidotransferase) from phosphoribosylpyrophosphate (PRPP) and glutamine ( Fig.…”

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confidence: 99%

PurF-Independent Phosphoribosyl Amine Formation inyjgFMutants ofSalmonella entericaUtilizes the Tryptophan Biosynthetic Enzyme Complex Anthranilate Synthase-Phosphoribosyltransferase

2006

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In Salmonella enterica, the biosynthetic pathways for the generation of purines and the essential cofactor thiamine pyrophosphate branch after sharing five enzymatic steps. Phosphoribosyl amine (PRA) is the first intermediate in the common portion of the pathway and is generated from phosphoribosylpyrophosphate and glutamine by the PurF enzyme (phosphoribosylpyrophosphate amidotransferase). A null mutation in yjgF allows PurF-independent PRA formation by an unknown mechanism. The tryptophan biosynthetic enzyme complex anthranilate synthase-phosphoribosyltransferase, composed of the TrpD and TrpE proteins, was shown to be essential for PRA formation in strains lacking both yjgF and purF. The activity generating PRA in a yjgF mutant background has features that distinguish it from the TrpDE-mediated PRA formation shown previously for this enzyme in strains with an active copy of yjgF. The data presented here are consistent with a model in which the absence of YjgF uncovers a new catalytic activity of TrpDE.

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The de-repression of thiamine biosynthesis by adenosine a tool for investigating this biosynthetic pathway

Cited by 33 publications

References 14 publications

Effect of Amino Acids and Purine Bases on Thiamine Synthesis by Escherichia coli

Effect of Amino Acids and Purine Bases on Thiamine Synthesis by Escherichia coli

Metabolic Flux in Both the Purine Mononucleotide and Histidine Biosynthetic Pathways Can Influence Synthesis of the Hydroxymethyl Pyrimidine Moiety of Thiamine in Salmonella enterica

PurF-Independent Phosphoribosyl Amine Formation inyjgFMutants ofSalmonella entericaUtilizes the Tryptophan Biosynthetic Enzyme Complex Anthranilate Synthase-Phosphoribosyltransferase

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