3PDT
Crystal Structure of the C-terminal Truncated Alpha-Kinase Domain of Myosin Heavy chain Kinase
Summary for 3PDT
| Entry DOI | 10.2210/pdb3pdt/pdb |
| Descriptor | Myosin heavy chain kinase A, MAGNESIUM ION, ZINC ION, ... (6 entities in total) |
| Functional Keywords | protein kinase like fold, protein kinase, atp binding, nucleotide binding, serine/threonine kinase, alpha-kinase, transferase |
| Biological source | Dictyostelium discoideum (Slime mold) |
| Total number of polymer chains | 1 |
| Total formula weight | 31764.90 |
| Authors | |
| Primary citation | Crawley, S.W.,Gharaei, M.S.,Ye, Q.,Yang, Y.,Raveh, B.,London, N.,Schueler-Furman, O.,Jia, Z.,Cote, G.P. Autophosphorylation Activates Dictyostelium Myosin II Heavy Chain Kinase A by Providing a Ligand for an Allosteric Binding Site in the {alpha}-Kinase Domain. J.Biol.Chem., 286:2607-2616, 2011 Cited by PubMed Abstract: Dictyostelium discoideum myosin II heavy chain kinase A (MHCK A), a member of the atypical α-kinase family, phosphorylates sites in the myosin II tail that block filament assembly. Here we show that the catalytic activity of A-CAT, the α-kinase domain of MHCK A (residues 552-841), is severely inhibited by the removal of a disordered C-terminal tail sequence (C-tail; residues 806-841). The key residue in the C-tail was identified as Thr(825), which was found to be constitutively autophosphorylated. Dephosphorylation of Thr(825) using shrimp alkaline phosphatase decreased A-CAT activity. The activity of a truncated A-CAT lacking Thr(825) could be rescued by P(i), phosphothreonine, and a phosphorylated peptide, but not by threonine, glutamic acid, aspartic acid, or an unphosphorylated peptide. These results focused attention on a P(i)-binding pocket located in the C-terminal lobe of A-CAT. Mutational analysis demonstrated that the P(i)-pocket was essential for A-CAT activity. Based on these results, it is proposed that autophosphorylation of Thr(825) activates ACAT by providing a covalently tethered ligand for the P(i)-pocket. Ab initio modeling studies using the Rosetta FloppyTail and FlexPepDock protocols showed that it is feasible for the phosphorylated Thr(825) to dock intramolecularly into the P(i)-pocket. Allosteric activation is predicted to involve a conformational change in Arg(734), which bridges the bound P(i) to Asp(762) in a key active site loop. Sequence alignments indicate that a comparable regulatory mechanism is likely to be conserved in Dictyostelium MHCK B-D and metazoan eukaryotic elongation factor-2 kinases. PubMed: 21071445DOI: 10.1074/jbc.M110.177014 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.8 Å) |
Structure validation
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