National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM81303
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM44757
米国
National Institutes of Health/National Institute on Aging (NIH/NIA)
AG32961
米国
引用
ジャーナル: Nat Commun / 年: 2017 タイトル: Structural basis for high-affinity actin binding revealed by a β-III-spectrin SCA5 missense mutation. 著者: Adam W Avery / Michael E Fealey / Fengbin Wang / Albina Orlova / Andrew R Thompson / David D Thomas / Thomas S Hays / Edward H Egelman / 要旨: Spinocerebellar ataxia type 5 (SCA5) is a neurodegenerative disease caused by mutations in the cytoskeletal protein β-III-spectrin. Previously, a SCA5 mutation resulting in a leucine-to-proline ...Spinocerebellar ataxia type 5 (SCA5) is a neurodegenerative disease caused by mutations in the cytoskeletal protein β-III-spectrin. Previously, a SCA5 mutation resulting in a leucine-to-proline substitution (L253P) in the actin-binding domain (ABD) was shown to cause a 1000-fold increase in actin-binding affinity. However, the structural basis for this increase is unknown. Here, we report a 6.9 Å cryo-EM structure of F-actin complexed with the L253P ABD. This structure, along with co-sedimentation and pulsed-EPR measurements, demonstrates that high-affinity binding caused by the CH2-localized mutation is due to opening of the two CH domains. This enables CH1 to bind actin aided by an unstructured N-terminal region that becomes α-helical upon binding. This helix is required for association with actin as truncation eliminates binding. Collectively, these results shed light on the mechanism by which β-III-spectrin, and likely similar actin-binding proteins, interact with actin, and how this mechanism can be perturbed to cause disease.
根拠: microscopy, helical filament was observed by negative staining and Cryo-EM
タイプ
名称
対称操作
数
identity operation
1_555
1
Buried area
36340 Å2
ΔGint
-117 kcal/mol
Surface area
108660 Å2
対称性
らせん対称: (回転対称性: 1 / Dyad axis: no / N subunits divisor: 1 / Num. of operations: 20 / Rise per n subunits: 27.25 Å / Rotation per n subunits: -166.87 °)
詳細
THE ASSEMBLY REPRESENTED IN THIS ENTRY HAS REGULAR HELICAL SYMMETRY WITH THE FOLLOWING PARAMETERS: ROTATION PER SUBUNIT (TWIST) = -166.87 DEGREES RISE PER SUBUNIT (HEIGHT) = 27.25 ANGSTROMS
平均露光時間: 3 sec. / 電子線照射量: 20 e/Å2 / 検出モード: INTEGRATING フィルム・検出器のモデル: FEI FALCON II (4k x 4k) 詳細: Images were stored containing seven parts, where each part represented a set of frames corresponding to a dose of ~20 electrons per Angstrom^2. The full dose image stack was used for the ...詳細: Images were stored containing seven parts, where each part represented a set of frames corresponding to a dose of ~20 electrons per Angstrom^2. The full dose image stack was used for the estimation of the CTF as well as for boxing filaments. Only the first two parts were used for the reconstruction (~5 electrons per Angstrom^2).
画像スキャン
動画フレーム数/画像: 7
-
解析
ソフトウェア
名称: PHENIX / バージョン: dev_2471: / 分類: 精密化
EMソフトウェア
ID
名称
カテゴリ
1
EMAN2
粒子像選択
2
EPU
画像取得
4
CTFFIND3
CTF補正
7
Rosetta
モデルフィッティング
9
SPIDER
初期オイラー角割当
10
SPIDER
最終オイラー角割当
12
SPIDER
3次元再構成
13
PHENIX
モデル精密化
14
Coot
モデル精密化
CTF補正
タイプ: PHASE FLIPPING AND AMPLITUDE CORRECTION
らせん対称
回転角度/サブユニット: -166.87 ° / 軸方向距離/サブユニット: 27.25 Å / らせん対称軸の対称性: C1
3次元再構成
解像度: 7 Å / 解像度の算出法: OTHER / 粒子像の数: 12443 / アルゴリズム: BACK PROJECTION / 詳細: model-map FSC 0.38 cut-off / 対称性のタイプ: HELICAL