5A65
Crystal structure of mouse thiamine triphosphatase in complex with thiamine diphosphate, orthophosphate and magnesium ions.
Summary for 5A65
| Entry DOI | 10.2210/pdb5a65/pdb |
| Related | 5A5Y 5A60 5A61 5A64 5A66 5A67 5A68 |
| Descriptor | THIAMINE TRIPHOSPHATASE, MAGNESIUM ION, THIAMINE DIPHOSPHATE, ... (6 entities in total) |
| Functional Keywords | triphosphate tunnel metalloenzyme, hydrolase |
| Biological source | MUS MUSCULUS (HOUSE MOUSE) |
| Cellular location | Cytoplasm : Q8JZL3 |
| Total number of polymer chains | 2 |
| Total formula weight | 48601.26 |
| Authors | Martinez, J.,Truffault, V.,Hothorn, M. (deposition date: 2015-06-24, release date: 2015-08-05, Last modification date: 2024-01-10) |
| Primary citation | Martinez, J.,Truffault, V.,Hothorn, M. Structural Determinants for Substrate Binding and Catalysis in Triphosphate Tunnel Metalloenzymes. J.Biol.Chem., 290:23348-, 2015 Cited by PubMed Abstract: Triphosphate tunnel metalloenzymes (TTMs) are present in all kingdoms of life and catalyze diverse enzymatic reactions such as mRNA capping, the cyclization of adenosine triphosphate, the hydrolysis of thiamine triphosphate, and the synthesis and breakdown of inorganic polyphosphates. TTMs have an unusual tunnel domain fold that harbors substrate- and metal co-factor binding sites. It is presently poorly understood how TTMs specifically sense different triphosphate-containing substrates and how catalysis occurs in the tunnel center. Here we describe substrate-bound structures of inorganic polyphosphatases from Arabidopsis and Escherichia coli, which reveal an unorthodox yet conserved mode of triphosphate and metal co-factor binding. We identify two metal binding sites in these enzymes, with one co-factor involved in substrate coordination and the other in catalysis. Structural comparisons with a substrate- and product-bound mammalian thiamine triphosphatase and with previously reported structures of mRNA capping enzymes, adenylate cyclases, and polyphosphate polymerases suggest that directionality of substrate binding defines TTM catalytic activity. Our work provides insight into the evolution and functional diversification of an ancient enzyme family. PubMed: 26221030DOI: 10.1074/JBC.M115.674473 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.98 Å) |
Structure validation
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