5wc0
From Proteopedia
katanin hexamer in spiral conformation
Structural highlights
Function[KTNA1_CAEEL] Catalytic subunit of a complex which severs microtubules in an ATP-dependent manner. Microtubule severing may promote rapid reorganization of cellular microtubule arrays. Required specifically for meiotic spindle formation in the female germline; the presence of this protein is inimical to the formation of mitotic spindles (PubMed:8027178, PubMed:10809666, PubMed:12885567). In body wall muscles, regulates organization of myosin thick filaments (PubMed:22621901).[HAMAP-Rule:MF_03023][1] [2] [3] [4] Publication Abstract from PubMedMicrotubule-severing enzymes katanin, spastin and fidgetin are AAA ATPases important for the biogenesis and maintenance of complex microtubule arrays in axons, spindles and cilia. Because of a lack of known 3D structures for these enzymes, their mechanism of action has remained poorly understood. Here we report the X-ray crystal structure of the monomeric AAA katanin module from Caenorhabditis elegans and cryo-EM reconstructions of the hexamer in two conformations. The structures reveal an unexpected asymmetric arrangement of the AAA domains mediated by structural elements unique to microtubule-severing enzymes and critical for their function. The reconstructions show that katanin cycles between open spiral and closed ring conformations, depending on the ATP occupancy of a gating protomer that tenses or relaxes interprotomer interfaces. Cycling of the hexamer between these conformations would provide the power stroke for microtubule severing. Katanin spiral and ring structures shed light on power stroke for microtubule severing.,Zehr E, Szyk A, Piszczek G, Szczesna E, Zuo X, Roll-Mecak A Nat Struct Mol Biol. 2017 Aug 7. doi: 10.1038/nsmb.3448. PMID:28783150[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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