French Infrastructure for Integrated Structural Biology
ANR-10-INSB-05-02
フランス
European Molecular Biology Organization
ALTF441-2017
フランス
引用
ジャーナル: Commun Biol / 年: 2020 タイトル: Structural insights into ATP hydrolysis by the MoxR ATPase RavA and the LdcI-RavA cage-like complex. 著者: Matthew Jessop / Benoit Arragain / Roger Miras / Angélique Fraudeau / Karine Huard / Maria Bacia-Verloop / Patrice Catty / Jan Felix / Hélène Malet / Irina Gutsche / 要旨: The hexameric MoxR AAA+ ATPase RavA and the decameric lysine decarboxylase LdcI form a 3.3 MDa cage, proposed to assist assembly of specific respiratory complexes in E. coli. Here, we show that ...The hexameric MoxR AAA+ ATPase RavA and the decameric lysine decarboxylase LdcI form a 3.3 MDa cage, proposed to assist assembly of specific respiratory complexes in E. coli. Here, we show that inside the LdcI-RavA cage, RavA hexamers adopt an asymmetric spiral conformation in which the nucleotide-free seam is constrained to two opposite orientations. Cryo-EM reconstructions of free RavA reveal two co-existing structural states: an asymmetric spiral, and a flat C2-symmetric closed ring characterised by two nucleotide-free seams. The closed ring RavA state bears close structural similarity to the pseudo two-fold symmetric crystal structure of the AAA+ unfoldase ClpX, suggesting a common ATPase mechanism. Based on these structures, and in light of the current knowledge regarding AAA+ ATPases, we propose different scenarios for the ATP hydrolysis cycle of free RavA and the LdcI-RavA cage-like complex, and extend the comparison to other AAA+ ATPases of clade 7.
pH: 7.9 詳細: 20 mM Tris pH 7.9, 300 mM NaCl, 2 mM ADP, 10 mM MgCl 2 , 0.1 mM PLP and 1 mM DTT
凍結
凍結剤: ETHANE
詳細
Concentrations of LdcI and RavA were 0.38 mg/ml (4.67 microM) and 0.6 mg/ml (10.64 microM) respectively.
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電子顕微鏡法
顕微鏡
FEI POLARA 300
詳細
Data collection was performed on an FEI Polara microscope operated at 300 kV. Movies of 40 frames were collected with a total exposure time of 8s and a total dose of 40e-/Angstrom^2 on a K2 summit direct electron detector (Gatan) at a magnification of 41270x, corresponding to 1.21 Angstrom/pixel at the specimen level.
倍率(補正後): 41270 / 照射モード: FLOOD BEAM / 撮影モード: BRIGHT FIELD
実験機器
モデル: Tecnai Polara / 画像提供: FEI Company
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画像解析
粒子像選択
選択した数: 18902 詳細: The cleanded dataset contains 11866 particles. Dataset expansion (C5) resulted in a dataset containing 59330 particles.
初期モデル
モデルのタイプ: INSILICO MODEL In silico モデル: The initial 3D model based on 2D class averages was calculated with sxviper (SPARX) (Hohn et al., 2007) imposing D5 symmetry.
source_name: PDB, initial_model_type: experimental model
詳細
Local resolution estimation and subsequent filtering of maps were performed in Relion3.0. For fitting of atomic models in the resulting filtered maps, we used the previously-determined X-ray structures of LdcI (PDB ID: 3N75) (Kanjee et al., 2011) and RavA (PDB ID: 3NBX) (El Bakkouri et al., 2010). In each map, two decameric LdcI molecules extracted from PDB 3N75 and one spiral RavA hexamer extracted from a continuous RavA helix generated from PDB 3NBX were fitted separately using iMODFIT (Lopez-Blanco and Chacon, 2013), followed by a single round of B-factor (ADP) refinement in Phenix.
精密化
プロトコル: FLEXIBLE FIT
得られたモデル
PDB-6q7m: Spiral structure of E. coli RavA in the RavA-LdcI cage-like complex