4Y25

Bacterial polysaccharide outer membrane secretin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.82 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.237 

wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

Structural Basis for Translocation of a Biofilm-supporting Exopolysaccharide across the Bacterial Outer Membrane

Wang, Y.Andole Pannuri, A.Ni, D.Zhou, H.Cao, X.Lu, X.Romeo, T.Huang, Y.

(2016) J Biol Chem 291: 10046-10057

  • DOI: https://doi.org/10.1074/jbc.M115.711762
  • Primary Citation of Related Structures:  
    4Y25

  • PubMed Abstract: 

    The partially de-N-acetylated poly-β-1,6-N-acetyl-d-glucosamine (dPNAG) polymer serves as an intercellular biofilm adhesin that plays an essential role for the development and maintenance of integrity of biofilms of diverse bacterial species. Translocation of dPNAG across the bacterial outer membrane is mediated by a tetratricopeptide repeat-containing outer membrane protein, PgaA. To understand the molecular basis of dPNAG translocation, we determined the crystal structure of the C-terminal transmembrane domain of PgaA (residues 513-807). The structure reveals that PgaA forms a 16-strand transmembrane β-barrel, closed by four loops on the extracellular surface. Half of the interior surface of the barrel that lies parallel to the translocation pathway is electronegative, suggesting that the corresponding negatively charged residues may assist the secretion of the positively charged dPNAG polymer. In vivo complementation assays in a pgaA deletion bacterial strain showed that a cluster of negatively charged residues proximal to the periplasm is necessary for biofilm formation. Biochemical analyses further revealed that the tetratricopeptide repeat domain of PgaA binds directly to the N-deacetylase PgaB and is critical for biofilm formation. Our studies support a model in which the positively charged PgaB-bound dPNAG polymer is delivered to PgaA through the PgaA-PgaB interaction and is further targeted to the β-barrel lumen of PgaA potentially via a charge complementarity mechanism, thus priming the translocation of dPNAG across the bacterial outer membrane.


  • Organizational Affiliation

    From the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China, University of Chinese Academy of Sciences, Beijing 100049, China.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Poly-beta-1,6-N-acetyl-D-glucosamine export protein311Escherichia coli K-12Mutation(s): 0 
Gene Names: pgaAycdSb1024JW1010
Membrane Entity: Yes 
UniProt
Find proteins for P69434 (Escherichia coli (strain K12))
Explore P69434 
Go to UniProtKB:  P69434
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP69434
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.82 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.237 
  • Space Group: P 63 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 143.972α = 90
b = 143.972β = 90
c = 90.56γ = 120
Software Package:
Software NamePurpose
HKL-2000data processing
PHENIXphasing
PHENIXmodel building
PHENIXrefinement
Cootmodel building
Cootrefinement

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Natural Science Foundation of ChinaChina31470743 and 31170698
Ministry of Science and Technology of P.R.China 973 ProjectChina2013CB910603 and 2012CB917302
Chinese Academy of SciencesChinaXDB08020302
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesGM059969 and GM066794
University of Florida CHRIS projectUnited StatesFLA-MCS-004949

Revision History  (Full details and data files)

  • Version 1.0: 2016-03-16
    Type: Initial release
  • Version 1.1: 2016-06-01
    Changes: Database references
  • Version 1.2: 2017-10-18
    Changes: Author supporting evidence, Database references, Derived calculations
  • Version 1.3: 2022-03-23
    Changes: Author supporting evidence, Database references
  • Version 1.4: 2024-05-29
    Changes: Data collection