Filling the gap of intracellular dephosphorylation in the Plasmodium falciparum vitamin B1 biosynthesis

Knöckel, Julia; Bergmann, Bärbel; Müller, Ingrid; Rathaur, Sushma; Walter, Rolf D.; Wrenger, Carsten

doi:10.1016/j.molbiopara.2007.10.010

Cited by 17 publications

(20 citation statements)

References 17 publications

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“…The activity profile of the Sa GTPase was analysed in 96-well microtiter plate by performing a spectrophotometric assay with minor modifications [48], [49]. Briefly, the reaction was carried out at 37°C in a total volume of 100 µl 100 mM MOPS, pH 7.5, containing 1 mM MgCl 2 and 1 mM of the respective substrates: GTP, ATP, CTP, ADP, AMP, TMP, TPP, glucose 6-phosphate, fructose 6-phosphate, ribose 5-phosphate, phosphoryl-ribose pyrophosphate and pyridoxal 5-phosphate.…”

Section: Methodsmentioning

confidence: 99%

The Vitamin B1 Metabolism of Staphylococcus aureus Is Controlled at Enzymatic and Transcriptional Levels

et al. 2009

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Vitamin B1 is in its active form thiamine pyrophosphate (TPP), an essential cofactor for several key enzymes in the carbohydrate metabolism. Mammals must salvage this crucial nutrient from their diet in order to complement the deficiency of de novo synthesis. In the human pathogenic bacterium Staphylococcus aureus, two operons were identified which are involved in vitamin B1 metabolism. The first operon encodes for the thiaminase type II (TenA), 4-amino-5-hydroxymethyl-2-methylpyrimidine kinase (ThiD), 5-(2-hydroxyethyl)-4-methylthiazole kinase (ThiM) and thiamine phosphate synthase (ThiE). The second operon encodes a phosphatase, an epimerase and the thiamine pyrophosphokinase (TPK). The open reading frames of the individual operons were cloned, their corresponding proteins were recombinantly expressed and biochemically analysed. The kinetic properties of the enzymes as well as the binding of TPP to the in vitro transcribed RNA of the proposed operons suggest that the vitamin B1 homeostasis in S. aureus is strongly regulated at transcriptional as well as enzymatic levels.

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Section: Methodsmentioning

confidence: 99%

The Vitamin B1 Metabolism of Staphylococcus aureus Is Controlled at Enzymatic and Transcriptional Levels

et al. 2009

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“…The latter reveals a broad substrate spectrum and therefore it is questionable whether this enzyme is solely responsible for the dephosphorylation of B6 vitamers [20, 31]. The PdxK catalyses the phosphorylation of pyridoxal but also accepts the other B6 vitamers as substrate [20, 32].…”

Section: Introductionmentioning

confidence: 99%

Vitamin B6-Dependent Enzymes in the Human Malaria ParasitePlasmodium falciparum: A Druggable Target?

Kronenberger

Lindner

Meissner

et al. 2014

BioMed Research International

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Malaria is a deadly infectious disease which affects millions of people each year in tropical regions. There is no effective vaccine available and the treatment is based on drugs which are currently facing an emergence of drug resistance and in this sense the search for new drug targets is indispensable. It is well established that vitamin biosynthetic pathways, such as the vitamin B6 de novo synthesis present in Plasmodium, are excellent drug targets. The active form of vitamin B6, pyridoxal 5-phosphate, is, besides its antioxidative properties, a cofactor for a variety of essential enzymes present in the malaria parasite which includes the ornithine decarboxylase (ODC, synthesis of polyamines), the aspartate aminotransferase (AspAT, involved in the protein biosynthesis), and the serine hydroxymethyltransferase (SHMT, a key enzyme within the folate metabolism).

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“…In all cases, transfection of circular plasmid DNA was carried out using the method described in [28][29][30], with the modification of using 1 μg/μl Bsd (Sigma) to select for Bsd-resistant parasites. To generate co-transfectants, either schizonts of the transgenic parasite line Pf Pdx1-Strep were used to infect pARL-Pf Pdx2-Myc-Bsd-pre-loaded erythrocytes or Pf Pdx1-Strep ring-stage parasites were electroporated directly with the pARL-Pf Pdx2-Myc-Bsd plasmid DNA as described above.…”

Section: Generation Of Transgenic P Falciparum Cell Linesmentioning

confidence: 99%

The antioxidative effect of de novo generated vitamin B6 in Plasmodium falciparum validated by protein interference

Knöckel

Müller

Butzloff

et al. 2012

Biochemical Journal

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The malaria parasite Plasmodium falciparum is able to synthesize de novo PLP (pyridoxal 5'-phosphate), the active form of vitamin B6. In the present study, we have shown that the de novo synthesized PLP is used by the parasite to detoxify 1O2 (singlet molecular oxygen), a highly destructive reactive oxygen species arising from haemoglobin digestion. The formation of 1O2 and the response of the parasite were monitored by live-cell fluorescence microscopy, by transcription analysis and by determination of PLP levels in the parasite. Pull-down experiments of transgenic parasites overexpressing the vitamin B6-biosynthetic enzymes PfPdx1 and PfPdx2 clearly demonstrated an interaction of the two proteins in vivo which results in an elevated PLP level from 12.5 μM in wild-type parasites to 36.6 μM in the PfPdx1/PfPdx2-overexpressing cells and thus to a higher tolerance towards 1O2. In contrast, by applying the dominant-negative effect on the cellular level using inactive mutants of PfPdx1 and PfPdx2, P. falciparum becomes susceptible to 1O2. Our results demonstrate clearly the crucial role of vitamin B6 biosynthesis in the detoxification of 1O2 in P. falciparum. Besides the known role of PLP as a cofactor of many essential enzymes, this second important task of the vitamin B6 de novo synthesis as antioxidant emphasizes the high potential of this pathway as a target of new anti-malarial drugs.

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Filling the gap of intracellular dephosphorylation in the Plasmodium falciparum vitamin B1 biosynthesis

Cited by 17 publications

References 17 publications

The Vitamin B1 Metabolism of Staphylococcus aureus Is Controlled at Enzymatic and Transcriptional Levels

The Vitamin B1 Metabolism of Staphylococcus aureus Is Controlled at Enzymatic and Transcriptional Levels

Vitamin B6-Dependent Enzymes in the Human Malaria ParasitePlasmodium falciparum: A Druggable Target?

The antioxidative effect of de novo generated vitamin B6 in Plasmodium falciparum validated by protein interference

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