ジャーナル: Structure / 年: 2010 タイトル: Local and global mobility in the ClpA AAA+ chaperone detected by cryo-electron microscopy: functional connotations. 著者: Grégory Effantin / Takashi Ishikawa / Gian Marco De Donatis / Michael R Maurizi / Alasdair C Steven / 要旨: The ClpA chaperone combines with the ClpP peptidase to perform targeted proteolysis in the bacterial cytoplasm. ClpA monomer has an N-terminal substrate-binding domain and two AAA+ ATPase domains (D1 ...The ClpA chaperone combines with the ClpP peptidase to perform targeted proteolysis in the bacterial cytoplasm. ClpA monomer has an N-terminal substrate-binding domain and two AAA+ ATPase domains (D1 and D2). ClpA hexamers stack axially on ClpP heptamers to form the symmetry-mismatched protease. We used cryo-electron microscopy to visualize the ClpA-ATPgammaS hexamer, in the context of ClpAP complexes. Two segments lining the axial channel show anomalously low density, indicating that these motifs, which have been implicated in substrate translocation, are mobile. We infer that ATP hydrolysis is accompanied by substantial structural changes in the D2 but not the D1 tier. The entire N domain is rendered invisible by large-scale fluctuations. When deletions of 10 and 15 residues were introduced into the linker, N domain mobility was reduced but not eliminated and changes were observed in enzymatic activities. Based on these observations, we present a pseudo-atomic model of ClpAP holoenzyme, a dynamic proteolytic nanomachine.
全体 : E.Coli ClpA in complex with ClpP, both wild type
全体
名称: E.Coli ClpA in complex with ClpP, both wild type
要素
試料: E.Coli ClpA in complex with ClpP, both wild type
タンパク質・ペプチド: clpA
-
超分子 #1000: E.Coli ClpA in complex with ClpP, both wild type
超分子
名称: E.Coli ClpA in complex with ClpP, both wild type / タイプ: sample / ID: 1000 集合状態: One homohexamer of ClpA binds to one tetradecamer of ClpP Number unique components: 1
分子量
実験値: 800 KDa / 理論値: 800 KDa
-
分子 #1: clpA
分子
名称: clpA / タイプ: protein_or_peptide / ID: 1 / Name.synonym: clpA 詳細: ClpA is in complex with ClpP but only ClpA was reconstructed コピー数: 6 / 集合状態: Hexamer / 組換発現: No