4A8D: Degp Dodecamer With Bound Omp

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.
PDB ID: 4A8DDownload
MMDB ID: 96431
PDB Deposition Date: 2011/11/20
Updated in MMDB: 2017/09
Experimental Method:
electron microscopy
Resolution: 28  Å
Source Organism:
Similar Structures:
Biological Unit for 4A8D: tridecameric; determined by author
Molecular Components in 4A8D
Label Count Molecule
Proteins (13 molecules)
Periplasmic Serine Endoprotease Degp(Gene symbol: degP)
Molecule annotation
Outer Membrane Protein C(Gene symbol: ompC)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB