3PV3

Structure of Legionella fallonii DegQ (S193A variant)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.1 Å
  • R-Value Free: 0.292 
  • R-Value Work: 0.224 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

The Legionella HtrA homologue DegQ is a self-compartmentizing protease that forms large 12-meric assemblies.

Wrase, R.Scott, H.Hilgenfeld, R.Hansen, G.

(2011) Proc.Natl.Acad.Sci.USA 108: 10490-10495

  • DOI: 10.1073/pnas.1101084108
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Proteases of the HtrA family are key factors dealing with folding stress in the periplasmatic compartment of prokaryotes. In Escherichia coli, the well-characterized HtrA family members DegS and DegP counteract the accumulation of unfolded outer-memb ...

    Proteases of the HtrA family are key factors dealing with folding stress in the periplasmatic compartment of prokaryotes. In Escherichia coli, the well-characterized HtrA family members DegS and DegP counteract the accumulation of unfolded outer-membrane proteins under stress conditions. Whereas DegS serves as a folding-stress sensor, DegP is a chaperone-protease facilitating refolding or degradation of defective outer-membrane proteins. Here, we report the 2.15-Å-resolution crystal structure of the second major chaperone-protease of the periplasm, DegQ from Legionella fallonii. DegQ assembles into large, cage-like 12-mers that form independently of unfolded substrate proteins. We provide evidence that 12-mer formation is essential for the degradation of substrate proteins but not for the chaperone activity of DegQ. In the current model for the regulation of periplasmatic chaperone-proteases, 6-meric assemblies represent important protease-resting states. However, DegQ is unable to form such 6-mers, suggesting divergent regulatory mechanisms for DegQ and DegP. To understand how the protease activity of DegQ is controlled, we probed its functional properties employing designed protein variants. Combining crystallographic, biochemical, and mutagenic data, we present a mechanistic model that suggests how protease activity of DegQ 12-mers is intrinsically regulated and how deleterious proteolysis by free DegQ 3-mers is prevented. Our study sheds light on a previously uncharacterized component of the prokaryotic stress-response system with implications for other members of the HtrA family.


    Organizational Affiliation

    Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
DegQ
A, B, C, D
451Legionella falloniiMutation(s): 0 
EC: 3.4.21.107
Find proteins for F8W673 (Legionella fallonii)
Go to UniProtKB:  F8W673
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Substrate peptide (Poly-Ala)
E, F, G, H
20N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
UNK
Query on UNK
E, F, G, H
L-PEPTIDE LINKINGC4 H9 N O2

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Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.1 Å
  • R-Value Free: 0.292 
  • R-Value Work: 0.224 
  • Space Group: H 3
Unit Cell:
Length (Å)Angle (°)
a = 155.030α = 90.00
b = 155.030β = 90.00
c = 260.600γ = 120.00
Software Package:
Software NamePurpose
PHASERphasing
SCALAdata scaling
REFMACrefinement
MOSFLMdata reduction
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-06-15
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance