Structural highlights
FunctionTBA1B_BOVIN 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 PubMedKinesin-14 is a unique minus-end-directed microtubule-based motor. A swinging motion of a class-specific N-terminal neck helix has been proposed to produce minus-end directionality. However, it is unclear how swinging of the neck helix is driven by ATP hydrolysis utilizing the highly conserved catalytic core among all kinesins. Here, using a motility assay, we show that in addition to the neck helix, the conserved five residues at the C-terminal region in kinesin-14, namely the neck mimic, are necessary to give kinesin-1 an ability to reverse its directionality toward the minus end of microtubules. Our structural analyses further demonstrate that the C-terminal neck mimic, in cooperation with conformational changes in the catalytic core during ATP binding, forms a kinesin-14 bundle with the N-terminal neck helix to swing toward the minus end of microtubules. Thus, the neck mimic plays a crucial role in coupling the chemical ATPase reaction with the mechanical cycle to produce the minus-end-directed motility of kinesin-14. Structural Basis of Backwards Motion in Kinesin-1-Kinesin-14 Chimera: Implication for Kinesin-14 Motility.,Yamagishi M, Shigematsu H, Yokoyama T, Kikkawa M, Sugawa M, Aoki M, Shirouzu M, Yajima J, Nitta R Structure. 2016 Aug 2;24(8):1322-34. doi: 10.1016/j.str.2016.05.021. Epub 2016, Jul 21. PMID:27452403[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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