4O4B
Crystal Structure of an Inositol hexakisphosphate kinase EhIP6KA as a fusion protein with maltose binding protein
Summary for 4O4B
| Entry DOI | 10.2210/pdb4o4b/pdb |
| Related | 4O4C 4O4D 4O4E 4O4F |
| Descriptor | Extracellular solute-binding protein family 1, Inositol hexakisphosphate kinase (3 entities in total) |
| Functional Keywords | pdkg kinase, transport protein-transferase complex, transport protein/transferase |
| Biological source | Escherichia coli More |
| Total number of polymer chains | 2 |
| Total formula weight | 73135.00 |
| Authors | Wang, H.,Shears, S.B. (deposition date: 2013-12-18, release date: 2014-06-18, Last modification date: 2023-09-20) |
| Primary citation | Wang, H.,DeRose, E.F.,London, R.E.,Shears, S.B. IP6K structure and the molecular determinants of catalytic specificity in an inositol phosphate kinase family. Nat Commun, 5:4178-4178, 2014 Cited by PubMed Abstract: Inositol trisphosphate kinases (IP3Ks) and inositol hexakisphosphate kinases (IP6Ks) each regulate specialized signalling activities by phosphorylating either InsP3 or InsP6 respectively. The molecular basis for these different kinase activities can be illuminated by a structural description of IP6K. Here we describe the crystal structure of an Entamoeba histolytica hybrid IP6K/IP3K, an enzymatic parallel to a 'living fossil'. Through molecular modelling and mutagenesis, we extrapolated our findings to human IP6K2, which retains vestigial IP3K activity. Two structural elements, an α-helical pair and a rare, two-turn 310 helix, together forge a substrate-binding pocket with an open clamshell geometry. InsP6 forms substantial contacts with both structural elements. Relative to InsP6, enzyme-bound InsP3 rotates 55° closer to the α-helices, which provide most of the protein's interactions with InsP3. These data reveal the molecular determinants of IP6K activity, and suggest an unusual evolutionary trajectory for a primordial kinase that could have favored efficient bifunctionality, before propagation of separate IP3Ks and IP6Ks. PubMed: 24956979DOI: 10.1038/ncomms5178 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.8 Å) |
Structure validation
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