4A9G

Symmetrized cryo-EM reconstruction of E. coli DegQ 24-mer in complex with beta-casein

Summary for 4A9G

• Entry DOI: 10.2210/pdb4a9g/pdb
• Related: 4A8A 4A8B 4A8C
• EMDB information: 1984
• Descriptor: PERIPLASMIC PH-DEPENDENT SERINE ENDOPROTEASE DEGQ (1 entity in total)
• Functional Keywords: chaperone, hydrolase
• Biological source: ESCHERICHIA COLI
• Cellular location: Periplasm : P39099
• Total number of polymer chains: 24
• Total formula weight: 1093023.94

Authors

Malet, H.,Canellas, F.,Sawa, J.,Yan, J.,Thalassinos, K.,Ehrmann, M.,Clausen, T.,Saibil, H.R. (deposition date: 2011-11-26, release date: 2012-01-11, Last modification date: 2024-05-08)

Primary citation

Malet, H.,Canellas, F.,Sawa, J.,Yan, J.,Thalassinos, K.,Ehrmann, M.,Clausen, T.,Saibil, H.R.
Newly Folded Substrates Inside the Molecular Cage of the Htra Chaperone Degq
Nat.Struct.Mol.Biol., 19:152-, 2012

PubMed Abstract: 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.

PubMed: 22245966
DOI: 10.1038/NSMB.2210

Experimental method

ELECTRON MICROSCOPY (7.5 Å)