Enzymes
| UniProtKB help_outline | 498 proteins |
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- Name help_outline H2O Identifier CHEBI:15377 (Beilstein: 3587155; CAS: 7732-18-5) help_outline Charge 0 Formula H2O InChIKeyhelp_outline XLYOFNOQVPJJNP-UHFFFAOYSA-N SMILEShelp_outline [H]O[H] 2D coordinates Mol file for the small molecule Search links Involved in 6,204 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline thiamine triphosphate Identifier CHEBI:58938 Charge -3 Formula C12H16N4O10P3S InChIKeyhelp_outline IWLROWZYZPNOFC-UHFFFAOYSA-K SMILEShelp_outline Cc1ncc(C[n+]2csc(CCOP([O-])(=O)OP([O-])(=O)OP([O-])([O-])=O)c2C)c(N)n1 2D coordinates Mol file for the small molecule Search links Involved in 3 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,431 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline phosphate Identifier CHEBI:43474 Charge -2 Formula HO4P InChIKeyhelp_outline NBIIXXVUZAFLBC-UHFFFAOYSA-L SMILEShelp_outline OP([O-])([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 992 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline thiamine diphosphate Identifier CHEBI:58937 Charge -2 Formula C12H16N4O7P2S InChIKeyhelp_outline AYEKOFBPNLCAJY-UHFFFAOYSA-L SMILEShelp_outline Cc1ncc(C[n+]2csc(CCOP([O-])(=O)OP([O-])([O-])=O)c2C)c(N)n1 2D coordinates Mol file for the small molecule Search links Involved in 12 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:11744 | RHEA:11745 | RHEA:11746 | RHEA:11747 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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Structural basis for the catalytic mechanism of mammalian 25-kDa thiamine triphosphatase.
Song J., Bettendorff L., Tonelli M., Markley J.L.
Mammalian soluble thiamine triphosphatase (ThTPase) is a 25-kDa cytosolic enzyme that specifically catalyzes the conversion of thiamine triphosphate (ThTP) to thiamine diphosphate and has an absolute requirement for divalent cations. We have investigated the kinetic properties of recombinant mouse ... >> More
Mammalian soluble thiamine triphosphatase (ThTPase) is a 25-kDa cytosolic enzyme that specifically catalyzes the conversion of thiamine triphosphate (ThTP) to thiamine diphosphate and has an absolute requirement for divalent cations. We have investigated the kinetic properties of recombinant mouse thiamine triphosphatase (mThTPase) and determined its solution structure by NMR spectroscopy. Residues responsible for binding Mg(2+) and ThTP were determined from NMR titration experiments. The binding of Mg(2+) induced only a minor local conformational change, whereas ThTP binding was found to cause a more global conformational change. We derived a structural model for the mThTPase.ThTP.Mg(2+) ternary complex and concluded from this that whereas free mThTPase has an open cleft fold, the enzyme in the ternary complex adopts a tunnel fold. Our results provide a functional rationale for a number of conserved residues and suggest an essential role for Mg(2+) in catalysis. We propose a mechanism underlying the high substrate specificity of mThTPase and discuss the possible role of water molecules in enzymatic catalysis. << Less
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Structural determinants of specificity and catalytic mechanism in mammalian 25-kDa thiamine triphosphatase.
Delvaux D., Kerff F., Murty M.R., Lakaye B., Czerniecki J., Kohn G., Wins P., Herman R., Gabelica V., Heuze F., Tordoir X., Maree R., Matagne A., Charlier P., De Pauw E., Bettendorff L.
<h4>Background</h4>Thiamine triphosphate (ThTP) is present in most organisms and might be involved in intracellular signaling. In mammalian cells, the cytosolic ThTP level is controlled by a specific thiamine triphosphatase (ThTPase), belonging to the CYTH superfamily of proteins. CYTH proteins ar ... >> More
<h4>Background</h4>Thiamine triphosphate (ThTP) is present in most organisms and might be involved in intracellular signaling. In mammalian cells, the cytosolic ThTP level is controlled by a specific thiamine triphosphatase (ThTPase), belonging to the CYTH superfamily of proteins. CYTH proteins are present in all superkingdoms of life and act on various triphosphorylated substrates.<h4>Methods</h4>Using crystallography, mass spectrometry and mutational analysis, we identified the key structural determinants of the high specificity and catalytic efficiency of mammalian ThTPase.<h4>Results</h4>Triphosphate binding requires three conserved arginines while the catalytic mechanism relies on an unusual lysine-tyrosine dyad. By docking of the ThTP molecule in the active site, we found that Trp-53 should interact with the thiazole part of the substrate molecule, thus playing a key role in substrate recognition and specificity. Sea anemone and zebrafish CYTH proteins, which retain the corresponding Trp residue, are also specific ThTPases. Surprisingly, the whole chromosome region containing the ThTPase gene is lost in birds.<h4>Conclusions</h4>The specificity for ThTP is linked to a stacking interaction between the thiazole heterocycle of thiamine and a tryptophan residue. The latter likely plays a key role in the secondary acquisition of ThTPase activity in early metazoan CYTH enzymes, in the lineage leading from cnidarians to mammals.<h4>General significance</h4>We show that ThTPase activity is not restricted to mammals as previously thought but is an acquisition of early metazoans. This, and the identification of critically important residues, allows us to draw an evolutionary perspective of the CYTH family of proteins. << Less
Biochim. Biophys. Acta 1830:4513-4523(2013) [PubMed] [EuropePMC]