- EMDB-5167: 3D reconstruction of a microtubule decorated with monomeric human... -
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基本情報
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データベース: EMDB / ID: EMD-5167
タイトル
3D reconstruction of a microtubule decorated with monomeric human kinesin (K349 construct) having ADP aluminum fluoride complex bound in the nucleotide pocket.
マップデータ
3D reconstruction of a microtubule decorated with monomeric human kinesin (K349 construct) having ADP aluminum fluoride complex bound in the nucleotide pocket.
試料
試料: Microtubule decorated with monomeric human kinesin (K349 construct) having ADP aluminum fluoride complex bound in the nucleotide pocket.
ジャーナル: Proc Natl Acad Sci U S A / 年: 2010 タイトル: An atomic-level mechanism for activation of the kinesin molecular motors. 著者: Charles V Sindelar / Kenneth H Downing / 要旨: Kinesin cytoskeletal motors convert the energy of ATP hydrolysis into stepping movement along microtubules. A partial model of this process has been derived from crystal structures, which show that ...Kinesin cytoskeletal motors convert the energy of ATP hydrolysis into stepping movement along microtubules. A partial model of this process has been derived from crystal structures, which show that movement of the motor domain relative to its major microtubule binding element, the switch II helix, is coupled to docking of kinesin's neck linker element along the motor domain. This docking would displace the cargo in the direction of travel and so contribute to a step. However, the crystal structures do not reveal how ATP binding and hydrolysis govern this series of events. We used cryoelectron microscopy to derive 8-9 A-resolution maps of four nucleotide states encompassing the microtubule-attached kinetic cycle of a kinesin motor. The exceptionally high quality of these maps allowed us to build in crystallographically determined conformations of kinesin's key subcomponents, yielding novel arrangements of kinesin's switch II helix and nucleotide-sensing switch loops. The resulting atomic models reveal a seesaw mechanism in which the switch loops, triggered by ATP binding, propel their side of the motor domain down and thereby elicit docking of the neck linker on the opposite side of the seesaw. Microtubules engage the seesaw mechanism by stabilizing the formation of extra turns at the N terminus of the switch II helix, which then serve as an anchor for the switch loops as they modulate the seesaw angle. These observations explain how microtubules activate kinesin's ATP-sensing machinery to promote cargo displacement and inform the mechanism of kinesin's ancestral relative, myosin.
ダウンロード / ファイル: emd_5167.map.gz / 形式: CCP4 / 大きさ: 165 KB / タイプ: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES)
注釈
3D reconstruction of a microtubule decorated with monomeric human kinesin (K349 construct) having ADP aluminum fluoride complex bound in the nucleotide pocket.
全体 : Microtubule decorated with monomeric human kinesin (K349 construc...
全体
名称: Microtubule decorated with monomeric human kinesin (K349 construct) having ADP aluminum fluoride complex bound in the nucleotide pocket.
要素
試料: Microtubule decorated with monomeric human kinesin (K349 construct) having ADP aluminum fluoride complex bound in the nucleotide pocket.
タンパク質・ペプチド: K349
タンパク質・ペプチド: Microtubule
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超分子 #1000: Microtubule decorated with monomeric human kinesin (K349 construc...
超分子
名称: Microtubule decorated with monomeric human kinesin (K349 construct) having ADP aluminum fluoride complex bound in the nucleotide pocket. タイプ: sample / ID: 1000 / Number unique components: 2
アルゴリズム: OTHER / 解像度のタイプ: BY AUTHOR / 解像度: 9.1 Å / 解像度の算出法: FSC 0.5 CUT-OFF / ソフトウェア - 名称: SPIDER,FREALIGN 詳細: Approximately 250,000 asymmetric units were averaged in the final reconstruction.
Protocol: Rigid Body. Regions in the crystal structure whose structure were found to differ from the EM map were excluded from the fitting procedure. These regions corresponded to the switch loops, helices alpha 3 and alpha 4 (switch II helix), and the neck linker.
精密化
空間: REAL / プロトコル: RIGID BODY FIT / 当てはまり具合の基準: Cross correlation