5T0Z

PelC from Geobacter metallireducens


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.25 Å
  • R-Value Free: 0.220 
  • R-Value Work: 0.173 
  • R-Value Observed: 0.176 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Oligomeric lipoprotein PelC guides Pel polysaccharide export across the outer membrane of Pseudomonas aeruginosa.

Marmont, L.S.Rich, J.D.Whitney, J.C.Whitfield, G.B.Almblad, H.Robinson, H.Parsek, M.R.Harrison, J.J.Howell, P.L.

(2017) Proc Natl Acad Sci U S A 114: 2892-2897

  • DOI: 10.1073/pnas.1613606114
  • Primary Citation of Related Structures:  
    5T0Z, 5T10, 5T11

  • PubMed Abstract: 
  • Secreted polysaccharides are important functional and structural components of bacterial biofilms. The opportunistic pathogen Pseudomonas aeruginosa produces the cationic exopolysaccharide Pel, which protects bacteria from aminoglycoside antibiotics and contributes to biofilm architecture through ionic interactions with extracellular DNA ...

    Secreted polysaccharides are important functional and structural components of bacterial biofilms. The opportunistic pathogen Pseudomonas aeruginosa produces the cationic exopolysaccharide Pel, which protects bacteria from aminoglycoside antibiotics and contributes to biofilm architecture through ionic interactions with extracellular DNA. A bioinformatics analysis of genome databases suggests that gene clusters for Pel biosynthesis are present in >125 bacterial species, yet little is known about how this biofilm exopolysaccharide is synthesized and exported from the cell. In this work, we characterize PelC, an outer membrane lipoprotein essential for Pel production. Crystal structures of PelC from Geobacter metallireducens and Paraburkholderia phytofirmans coupled with structure-guided disulfide cross-linking in P. aeruginosa suggest that PelC assembles into a 12- subunit ring-shaped oligomer. In this arrangement, an aromatic belt in proximity to its lipidation site positions the highly electronegative surface of PelC toward the periplasm. PelC is structurally similar to the Escherichia coli amyloid exporter CsgG; however, unlike CsgG, PelC does not possess membrane-spanning segments required for polymer export across the outer membrane. We show that the multidomain protein PelB with a predicted C-terminal β-barrel porin localizes to the outer membrane, and propose that PelC functions as an electronegative funnel to guide the positively charged Pel polysaccharide toward an exit channel formed by PelB. Together, our findings provide insight into the unique molecular architecture and export mechanism of the Pel apparatus, a widespread exopolysaccharide secretion system found in environmental and pathogenic bacteria.


    Organizational Affiliation

    Department of Biochemistry, University of Toronto, Toronto, ON, Canada M5S 1A8.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Lipoprotein, putativeA, B, C, D183Geobacter metallireducens GS-15Mutation(s): 0 
Gene Names: Gmet_1966
UniProt
Find proteins for Q39U79 (Geobacter metallireducens (strain ATCC 53774 / DSM 7210 / GS-15))
Explore Q39U79 
Go to UniProtKB:  Q39U79
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ39U79
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.25 Å
  • R-Value Free: 0.220 
  • R-Value Work: 0.173 
  • R-Value Observed: 0.176 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 59.931α = 90
b = 78.298β = 105.86
c = 85.136γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
DENZOdata reduction
SCALEPACKdata scaling
HKL-3000phasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2017-03-15
    Type: Initial release
  • Version 1.1: 2017-03-29
    Changes: Database references