ジャーナル: Nat Struct Mol Biol / 年: 2012 タイトル: Newly folded substrates inside the molecular cage of the HtrA chaperone DegQ. 著者: Hélène Malet / Flavia Canellas / Justyna Sawa / Jun Yan / Konstantinos Thalassinos / Michael Ehrmann / Tim Clausen / Helen R Saibil / 要旨: The HtrA protein family combines chaperone and protease activities and is essential for protein quality control in many organisms. Whereas the mechanisms underlying the proteolytic function of HtrA ...The HtrA protein family combines chaperone and protease activities and is essential for protein quality control in many organisms. Whereas the mechanisms underlying the proteolytic function of HtrA proteins are well characterized, their chaperone activity remains poorly understood. Here we describe cryo-EM structures of Escherichia coli DegQ in its 12- and 24-mer states in complex with model substrates, providing a structural model of HtrA chaperone action. Up to six lysozyme substrates bind inside the DegQ 12-mer cage and are visualized in a close-to-native state. An asymmetric reconstruction reveals the binding of a well-ordered lysozyme to four DegQ protomers. DegQ PDZ domains are located adjacent to substrate density and their presence is required for chaperone activity. The substrate-interacting regions appear conserved in 12- and 24-mer cages, suggesting a common mechanism of chaperone function.
Chain - #0 - Chain ID: A / Chain - #1 - Chain ID: B / Chain - #2 - Chain ID: C
ソフトウェア
名称: Chimera, Flex-EM
詳細
PDBEntryID_givenInChain. Protocol: Rigid body and flexible fitting. Protease and PDZ1 trimers extracted from 3STJ pdb entry. PDZ2 domain modelled with MODELLER from E. coli DegP pdb entry 3CS0.
精密化
空間: REAL / プロトコル: FLEXIBLE FIT / 当てはまり具合の基準: Cross-correlation, energy
得られたモデル
PDB-4a8a: Asymmetric cryo-EM reconstruction of E. coli DegQ 12-mer in complex with lysozyme