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Minimized average structure of GDP-bound dynamic microtubulesMinimized average structure of GDP-bound dynamic microtubules
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Structural highlights
FunctionTBA1A_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 PubMedDynamic instability, the stochastic switching between growth and shrinkage, is essential for microtubule function. This behavior is driven by GTP hydrolysis in the microtubule lattice and is inhibited by anticancer agents like Taxol. We provide insight into the mechanism of dynamic instability, based on high-resolution cryo-EM structures (4.7-5.6 A) of dynamic microtubules and microtubules stabilized by GMPCPP or Taxol. We infer that hydrolysis leads to a compaction around the E-site nucleotide at longitudinal interfaces, as well as movement of the alpha-tubulin intermediate domain and H7 helix. Displacement of the C-terminal helices in both alpha- and beta-tubulin subunits suggests an effect on interactions with binding partners that contact this region. Taxol inhibits most of these conformational changes, allosterically inducing a GMPCPP-like state. Lateral interactions are similar in all conditions we examined, suggesting that microtubule lattice stability is primarily modulated at longitudinal interfaces. High-Resolution Microtubule Structures Reveal the Structural Transitions in alphabeta-Tubulin upon GTP Hydrolysis.,Alushin GM, Lander GC, Kellogg EH, Zhang R, Baker D, Nogales E Cell. 2014 May 22;157(5):1117-29. doi: 10.1016/j.cell.2014.03.053. PMID:24855948[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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