ジャーナル: Proc Natl Acad Sci U S A / 年: 2008 タイトル: High-resolution cryo-EM structure of the F-actin-fimbrin/plastin ABD2 complex. 著者: Vitold E Galkin / Albina Orlova / Olga Cherepanova / Marie-Christine Lebart / Edward H Egelman / 要旨: Many actin binding proteins have a modular architecture, and calponin-homology (CH) domains are one such structurally conserved module found in numerous proteins that interact with F-actin. The ...Many actin binding proteins have a modular architecture, and calponin-homology (CH) domains are one such structurally conserved module found in numerous proteins that interact with F-actin. The manner in which CH-domains bind F-actin has been controversial. Using cryo-EM and a single-particle approach to helical reconstruction, we have generated 12-A-resolution maps of F-actin alone and F-actin decorated with a fragment of human fimbrin (L-plastin) containing tandem CH-domains. The high resolution allows an unambiguous fit of the crystal structure of fimbrin into the map. The interaction between fimbrin ABD2 (actin binding domain 2) and F-actin is different from any interaction previously observed or proposed for tandem CH-domain proteins, showing that the structural conservation of the CH-domains does not lead to a conserved mode of interaction with F-actin. Both the stapling of adjacent actin protomers and the additional closure of the nucleotide binding cleft in F-actin when the fimbrin fragment binds may explain how fimbrin can stabilize actin filaments. A mechanism is proposed where ABD1 of fimbrin becomes activated for binding a second actin filament after ABD2 is bound to a first filament, and this can explain how mutations of residues buried in the interface between ABD2 and ABD1 can rescue temperature-sensitive defects in actin.
分子量: 26764.367 Da / 分子数: 1 / 由来タイプ: 組換発現 / 由来: (組換発現) Homo sapiens (ヒト) / 発現宿主: Escherichia coli (大腸菌)
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実験情報
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実験
実験
手法: 電子顕微鏡法
EM実験
試料の集合状態: FILAMENT / 3次元再構成法: らせん対称体再構成法
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試料調製
構成要素
名称: Actin-Fimbrin ABD2 Complex / タイプ: COMPLEX 詳細: helical filament. rotation by -166.5 degrees about the z-axis (x=0, y=0), translation by 27.3 Angstroms along the z-axis