Crystal structure of the protease + PDZ1 domain of DegQ from Escherichia coli

Experimental Data Snapshot

  • Resolution: 2.60 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.186 

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Molecular adaptation of the DegQ protease to exert protein quality control in the bacterial cell envelope.

Sawa, J.Malet, H.Krojer, T.Canellas, F.Ehrmann, M.Clausen, T.

(2011) J Biol Chem 286: 30680-30690

  • DOI: https://doi.org/10.1074/jbc.M111.243832
  • Primary Citation of Related Structures:  
    3STI, 3STJ

  • PubMed Abstract: 

    To react to distinct stress situations and to prevent the accumulation of misfolded proteins, all cells employ a number of proteases and chaperones, which together set up an efficient protein quality control system. The functionality of proteins in the cell envelope of Escherichia coli is monitored by the HtrA proteases DegS, DegP, and DegQ. In contrast with DegP and DegS, the structure and function of DegQ has not been addressed in detail. Here, we show that substrate binding triggers the conversion of the resting DegQ hexamer into catalytically active 12- and 24-mers. Interestingly, substrate-induced oligomer reassembly and protease activation depends on the first PDZ domain but not on the second. Therefore, the regulatory mechanism originally identified in DegP should be a common feature of HtrA proteases, most of which encompass only a single PDZ domain. Using a DegQ mutant lacking the second PDZ domain, we determined the high resolution crystal structure of a dodecameric HtrA complex. The nearly identical domain orientation of protease and PDZ domains within 12- and 24-meric HtrA complexes reveals a conserved PDZ1 → L3 → LD/L1/L2 signaling cascade, in which loop L3 senses the repositioned PDZ1 domain of higher order, substrate-engaged particles and activates protease function. Furthermore, our in vitro and in vivo data imply a pH-related function of DegQ in the bacterial cell envelope.

  • Organizational Affiliation

    Institute of Molecular Pathology, A-1030 Vienna, Austria.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Protease degQ
A, B, C, D, E
A, B, C, D, E, F, G, H, I, J, K, L
345Escherichia coli K-12Mutation(s): 0 
Gene Names: degQhhoAb3234JW3203
EC: 3.4.21
Find proteins for P39099 (Escherichia coli (strain K12))
Explore P39099 
Go to UniProtKB:  P39099
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP39099
Sequence Annotations
  • Reference Sequence

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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
peptide (UNK)
Y [auth Z]
7Escherichia coliMutation(s): 0 
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.60 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.186 
  • Space Group: P 31
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 115.316α = 90
b = 115.316β = 90
c = 287.419γ = 120
Software Package:
Software NamePurpose
DNAdata collection
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-07-27
    Type: Initial release
  • Version 1.1: 2012-01-11
    Changes: Database references
  • Version 1.2: 2024-02-28
    Changes: Data collection, Database references