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See detailThiamine triphosphate synthesis in rat brain occurs in mitochondria and is coupled to the respiratory chain
Gangolf, Marjorie ULg; Wins, Pierre; Thiry, Marc ULg et al

in Journal of Biological Chemistry (2010), 285

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See detailThiaminylated adenine nucleotides — chemical synthesis, structural characterization and natural occurrence
Frederich, Michel ULg; Delvaux, David ULg; Gigliobianco, Tiziana ULg et al

in FEBS Journal (2009), 276(12), 32563268

Thiamine and its three phosphorylated derivatives (mono-, di- and triphosphate) occur naturally in most cells. Recently, we reported the presence of a fourth thiamine derivative, adenosine thiamine ... [more ▼]

Thiamine and its three phosphorylated derivatives (mono-, di- and triphosphate) occur naturally in most cells. Recently, we reported the presence of a fourth thiamine derivative, adenosine thiamine triphosphate (AThTP), produced in E. coli in response to carbon starvation. Here, we show that the chemical synthesis of AThTP leads to another new compound, adenosine thiamine diphosphate (thiaminylated ADP, AThDP), as a side product. The structure of both compounds was confirmed by mass spectrometry and 1H-, 13C- and 31P-NMR and some of their chemical properties were determined. Our results show an upfield shifting of the C-2 proton of the thiazolium ring in adenosine thiamine derivatives compared to the conventional thiamine phosphate derivatives. This modification of the electronic environment of the C-2 proton might be explained by a through-space interaction with the adenosine moiety, suggesting an U-shaped folding of adenosine thiamine derivatives. Such a structure where the C-2 proton is embedded in a closed conformation can be located using molecular modeling as an energy minimum. In E. coli, AThTP may account for 15% of total thiamine under energy stress. It is less abundant in eukaryotic organisms, but is consistently found in mammalian tissues and in some cell lines. Using a HPLC method, we show for the first time that AThDP may also occur in small amounts in E. coli and in vertebrate liver. The discovery of two natural thiamine adenine compounds further highlights the complexity and diversity of thiamine biochemistry, which is not restricted to the cofactor role of thiamine diphosphate. [less ▲]

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See detailThiamin diphosphate in biological chemistry: new aspects of thiamin metabolism, especially triphosphate derivatives acting other than as cofactors
Bettendorff, Lucien ULg; Wins, Pierre

in FEBS Journal (2009), 276(11), 2917-2925

Prokaryotes, yeasts and plants synthesize thiamine (vitamin B1) via complex pathways. Animal cells capture the vitamin through specific high-affinity transporters essential for internal thiamine ... [more ▼]

Prokaryotes, yeasts and plants synthesize thiamine (vitamin B1) via complex pathways. Animal cells capture the vitamin through specific high-affinity transporters essential for internal thiamine homeostasis. Inside the cells, thiamine is phosphorylated to higher phosphate derivatives. Thiamine diphosphate (ThDP) is the best-known thiamine compound for its role as an enzymatic cofactor. However, besides ThDP, at least three other thiamine phosphates occur naturally in most cells: thiamine monophosphate (ThMP), thiamine triphosphate (ThTP) and the recently discovered adenosine thiamine triphosphate (AThTP). It was suggested that ThTP has a specific neurophysiological role, but recent data are in favor of a much more basic metabolic function. During amino acid starvation, Escherichia coli accumulate ThTP possibly acting as a signal involved in the adaptation of the bacteria to changing nutritional conditions. In animal cells, ThTP can phosphorylate some proteins, but the physiological significance of this mechanism remains unknown. AThTP, recently discovered in E. coli, accumulates during carbon starvation and might act as an alarmone. Among the proteins involved in thiamine metabolism, thiamine transporters, thiamine pyrophosphokinase and a soluble 25-kDa thiamine triphosphatase have been characterized at the molecular level, in contrast to thiamine mono- and diphosphatases whose specificities remain to be proven. A soluble enzyme catalyzing the synthesis of AThTP from ThDP and ADP or ATP has been partially characterized in E. coli, but the mechanism of ThTP synthesis remains elusive. The data reviewed here illustrate the complexity of thiamine biochemistry, which is not restricted to the cofactor role of ThDP. [less ▲]

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See detailStructural basis for the catalytic mechanism of mammalian 25 kDa thiamine triphosphatase
Song, J.; Bettendorff, Lucien ULg; Tonelli, Marco et al

in Journal of Biological Chemistry (2008), 283

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See detailAdenylate Kinase-Independent Thiamine Triphosphate Accumulation under Severe Energy Stress in Escherichia Coli
Gigliobianco, Tiziana ULg; Lakaye, Bernard ULg; Makarchikov, Alexander F et al

in BMC Microbiology (2008), 8

BACKGROUND: Thiamine triphosphate (ThTP) exists in most organisms and might play a role in cellular stress responses. In E. coli, ThTP is accumulated in response to amino acid starvation but the mechanism ... [more ▼]

BACKGROUND: Thiamine triphosphate (ThTP) exists in most organisms and might play a role in cellular stress responses. In E. coli, ThTP is accumulated in response to amino acid starvation but the mechanism of its synthesis is still a matter of controversy. It has been suggested that ThTP is synthesized by an ATP-dependent specific thiamine diphosphate kinase. However, it is also known that vertebrate adenylate kinase 1 catalyzes ThTP synthesis at a very low rate and it has been postulated that this enzyme is responsible for ThTP synthesis in vivo. RESULTS: Here we show that bacterial, as vertebrate adenylate kinases are able to catalyze ThTP synthesis, but at a rate more than 106-fold lower than ATP synthesis. This activity is too low to explain the high rate of ThTP accumulation observed in E. coli during amino acid starvation. Moreover, bacteria from the heat-sensitive CV2 strain accumulate high amounts of ThTP (>50% of total thiamine) at 37 degrees C despite complete inactivation of adenylate kinase and a subsequent drop in cellular ATP. CONCLUSION: These results clearly demonstrate that adenylate kinase is not responsible for ThTP synthesis in vivo. Furthermore, they show that E. coli accumulate large amounts of ThTP under severe energy stress when ATP levels are very low, an observation not in favor of an ATP-dependent mechanisms for ThTP synthesis. [less ▲]

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See detailDiscovery of a natural thiamine adenine nucleotide
Bettendorff, Lucien ULg; Wirtzfeld, Barbara; Makarchikov, Alexander F et al

in Nature Chemical Biology (2007), 3(4), 211-212

Several important cofactors are adenine nucleotides with a vitamin as the catalytic moiety. Here, we report the discovery of the first adenine nucleotide containing vitamin B1: adenosine thiamine ... [more ▼]

Several important cofactors are adenine nucleotides with a vitamin as the catalytic moiety. Here, we report the discovery of the first adenine nucleotide containing vitamin B1: adenosine thiamine triphosphate (AThTP, 1), or thiaminylated ATP. We discovered AThTP in Escherichia coli and found that it accumulates specifically in response to carbon starvation, thereby acting as a signal rather than a cofactor. We detected smaller amounts in yeast and in plant and animal tissues. [less ▲]

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See detailNew evidence for a non-cofactor role of thiamine phosphate derivatives
Bettendorff, Lucien ULg

Scientific conference (2007)

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See detailAt the crossroad of thiamine degradation and biosynthesis
Bettendorff, Lucien ULg

in Nature Chemical Biology (2007), 3(8), 454-455

The physiological significance of thiaminase II has escaped our understanding for many years. The recent discovery of a new thiamine salvage pathway shows that this enzyme is involved in the regeneration ... [more ▼]

The physiological significance of thiaminase II has escaped our understanding for many years. The recent discovery of a new thiamine salvage pathway shows that this enzyme is involved in the regeneration of precursors for thiamine biosynthesis. [less ▲]

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See detailThiamine Diphosphate Adenylyl Transferase from E. Coli: Functional Characterization of the Enzyme Synthesizing Adenosine Thiamine Triphosphate
Makarchikov, Alexander F; Brans, Alain ULg; Bettendorff, Lucien ULg

in BMC Biochemistry (2007), 8

BACKGROUND: We have recently identified a new thiamine derivative, adenosine thiamine triphosphate (AThTP), in E. coli. In intact bacteria, this nucleotide is synthesized only in the absence of a ... [more ▼]

BACKGROUND: We have recently identified a new thiamine derivative, adenosine thiamine triphosphate (AThTP), in E. coli. In intact bacteria, this nucleotide is synthesized only in the absence of a metabolizable carbon source and quickly disappears as soon as the cells receive a carbon source such as glucose. Thus, we hypothesized that AThTP may be a signal produced in response to carbon starvation. RESULTS: Here we show that, in bacterial extracts, the biosynthesis of AThTP is carried out from thiamine diphosphate (ThDP) and ADP or ATP by a soluble high molecular mass nucleotidyl transferase. We partially purified this enzyme and characterized some of its functional properties. The enzyme activity had an absolute requirement for divalent metal ions, such as Mn2+ or Mg2+, as well as for a heat-stable soluble activator present in bacterial extracts. The enzyme has a pH optimum of 6.5-7.0 and a high Km for ThDP (5 mM), suggesting that, in vivo, the rate of AThTP synthesis is proportional to the free ThDP concentration. When ADP was used as the variable substrate at a fixed ThDP concentration, a sigmoid curve was obtained, with a Hill coefficient of 2.1 and an S0.5 value of 0.08 mM. The specificity of the AThTP synthesizing enzyme with respect to nucleotide substrate is restricted to ATP/ADP, and only ThDP can serve as the second substrate of the reaction. We tentatively named this enzyme ThDP adenylyl transferase (EC 2.7.7.65). CONCLUSION: This is the first demonstration of an enzyme activity transferring a nucleotidyl group on thiamine diphosphate to produce AThTP. The existence of a mechanism for the enzymatic synthesis of this compound is in agreement with the hypothesis of a non-cofactor role for thiamine derivatives in living cells. [less ▲]

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See detailThe antitrypanosomal drug melarsoprol competitively inhibits thiamin uptake in mouse neuroblastoma cells
Szyniarowski, Piotr; Bettendorff, Lucien ULg; Schweingruber, M. E.

in Cell Biology and Toxicology (2006), 22(3), 183-187

Melarsoprol is the main drug used for the treatment of late-stage sleeping sickness, although it causes severe side-effects such as encephalopathy and polyneuropathy leading to death in some patients ... [more ▼]

Melarsoprol is the main drug used for the treatment of late-stage sleeping sickness, although it causes severe side-effects such as encephalopathy and polyneuropathy leading to death in some patients. Recent data suggest that melarsoprol and its active metabolite melarsenoxide interfere with thiamin transport and metabolism in E. coli and yeast, but there are no data concerning their possible effects on thiamin metabolism in mammalian cells. We tested both drugs on thiamin transport in cultured mouse neuroblastoma cells using C-14-labeled thiamin. Melarsoprol, competitively inhibits high-affinity thiamin transport in mouse neuroblastoma cells with a K-i of 44 mu mol/L. However, the active compound melarsenoxide has no inhibitory effect. This suggests that the side effects of melarsoprol treatment are unlikely to be due to inhibition of thiamin transport by melarsenoxide, its main metabolite in the brain. [less ▲]

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See detailPig tissues express a catalytically inefficient 25-kDa thiamine triphosphatase: Insight in the catalytic mechanisms of this enzyme
Szyniarowski, Piotr; Lakaye, Bernard ULg; Czerniecki, Jan ULg et al

in Biochimica et Biophysica Acta - General Subjects (2005), 1725(1), 93-102

Thiamine triphosphate (ThTP) is found in most organisms and may be an intracellular signal molecule produced in response to stress. We have recently cloned the cDNA coding for a highly specific mammalian ... [more ▼]

Thiamine triphosphate (ThTP) is found in most organisms and may be an intracellular signal molecule produced in response to stress. We have recently cloned the cDNA coding for a highly specific mammalian 25-kDa thiamine triphosphatase. The enzyme was active in all mammalian species studied except pig, although the corresponding mRNA was present. In order to determine whether the very low ThTPase activity in pig tissues is due to the absence of the protein or to a lack of catalytic efficiency, we expressed human and pig ThTPase in E. coli as GST fusion proteins. The purified recombinant pig GST-ThTPase was found to be 2-3 orders of magnitude less active than human GST-ThTPase. Using site-directed mutagenesis, we show that, in particular, the change of Glu85 to lysine is responsible for decreased solubility and catalytic activity of the pig enzyme. Immunohistochemical studies revealed a distribution of the protein in pig brain very similar to the one reported in rodent brain. Thus, our results suggest that a 25-kDa protein homologous to hThTPase but practically devoid of enzyme activity is expressed in pig tissues. This raises the possibility that this protein may play a physiological role other than ThTP hydrolysis. [less ▲]

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See detailDistrribution of specific thiamine triphosphatase in biological objects
Makarchikov, Alexander F; Bettendorff, Lucien ULg

in News of Biomedical Sciences (2005), 2

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See detailNew perspectives on the cellular role of thiamine triphosphate and thiamine triphosphatase
Bettendorff, Lucien ULg; Wins, Pierre

in Patel, M. S.; Jordan, F. (Eds.) Thiamine: catalytic mechanisms and role in normal and disease states (2004)

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