5T0Z

PelC from Geobacter metallireducens


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.255 Å
  • R-Value Free: 0.220 
  • R-Value Work: 0.173 

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:  

  • 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 ...

    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

    Program in Molecular Structure & Function, The Hospital for Sick Children, Toronto, ON, Canada M5G 0A4.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Lipoprotein, putative
A, B, C, D
183Geobacter metallireducens (strain GS-15 / ATCC 53774 / DSM 7210)Mutation(s): 0 
Find proteins for Q39U79 (Geobacter metallireducens (strain GS-15 / ATCC 53774 / DSM 7210))
Go to UniProtKB:  Q39U79
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.255 Å
  • R-Value Free: 0.220 
  • R-Value Work: 0.173 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 59.931α = 90.00
b = 78.298β = 105.86
c = 85.136γ = 90.00
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PHENIXrefinement
HKL-3000phasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

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