7tqz | pdb_00007tqz

Apo CaKip3[2-482] in complex with a microtubule

spinqualitylabelsall models 7tqz, resolution 2.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7tqz is a 3 chain structure with sequence from Candida albicans and Sus scrofa. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GDP, GTP, MG, TA1 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [TBA1B_PIG] Tubulin is the major constituent of microtubules. It binds two moles of GTP, one at an exchangeable site on the beta chain and one at a non-exchangeable site on the alpha chain. Publication Abstract from PubMed Kinesin-8s are dual-activity motor proteins that can move processively on microtubules and depolymerize microtubule plus-ends, but their mechanism of combining these distinct activities remains unclear. We addressed this by obtaining cryo-EM structures (2.6-3.9 A) of Candida albicans Kip3 in different catalytic states on the microtubule lattice and on a curved microtubule end mimic. We also determined a crystal structure of microtubule-unbound CaKip3-ADP (2.0 A) and analyzed the biochemical activity of CaKip3 and kinesin-1 mutants. These data reveal that the microtubule depolymerization activity of kinesin-8 originates from conformational changes of its motor core that are amplified by dynamic contacts between its extended loop-2 and tubulin. On curved microtubule ends, loop-1 inserts into preceding motor domains, forming head-to-tail arrays of kinesin-8s that complement loop-2 contacts with curved tubulin and assist depolymerization. On straight tubulin protofilaments in the microtubule lattice, loop-2-tubulin contacts inhibit conformational changes in the motor core, but in the ADP-Pi state these contacts are relaxed, allowing neck-linker docking for motility. We propose that these tubulin shape-induced alternations between pro-microtubule-depolymerization and pro-motility kinesin states, regulated by loop-2, are the key to the dual activity of kinesin-8 motors. Kinesin-8-specific loop-2 controls the dual activities of the motor domain according to tubulin protofilament shape.,Hunter B, Benoit MPMH, Asenjo AB, Doubleday C, Trofimova D, Frazer C, Shoukat I, Sosa H, Allingham JS Nat Commun. 2022 Jul 20;13(1):4198. doi: 10.1038/s41467-022-31794-3. PMID:35859148 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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