4Y25

Bacterial polysaccharide outer membrane secretin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.821 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.232 

wwPDB Validation 3D Report Full Report


This is version 1.2 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: 10.1074/jbc.M115.711762

  • 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. Translo ...

    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: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Poly-beta-1,6-N-acetyl-D-glucosamine export protein
A
311Escherichia coli (strain K12)Mutation(s): 0 
Gene Names: pgaA (ycdS)
Find proteins for P69434 (Escherichia coli (strain K12))
Go to UniProtKB:  P69434
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.821 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.232 
  • Space Group: P 63 2 2
Unit Cell:
Length (Å)Angle (°)
a = 143.972α = 90.00
b = 143.972β = 90.00
c = 90.560γ = 120.00
Software Package:
Software NamePurpose
Cootrefinement
HKL-2000data processing
PHENIXmodel building
Cootmodel building
PHENIXphasing
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



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 SciencesUnited StatesGM059969 and GM066794
University of Florida CHRIS projectUnited StatesFLA-MCS-004949

Revision History 

  • Version 1.0: 2016-03-16
    Type: Initial release
  • Version 1.1: 2016-06-01
    Type: Database references
  • Version 1.2: 2017-10-18
    Type: Author supporting evidence, Database references, Derived calculations