4AFK

In meso structure of alginate transporter, AlgE, from Pseudomonas aeruginosa, PAO1


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.897 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.163 

wwPDB Validation 3D Report Full Report


This is version 1.4 of the entry. See complete history

Literature

A Conformational Landscape for Alginate Secretion Across the Outer Membrane of Pseudomonas Aeruginosa.

Tan, J.Rouse, S.L.Li, D.Pye, V.E.Vogeley, L.Brinth, A.R.El Arnaout, T.Whitney, J.C.Howell, P.L.Sansom, M.S.P.Caffrey, M.

(2014) Acta Crystallogr.,Sect.D 70: 2054

  • DOI: 10.1107/S1399004714001850
  • Primary Citation of Related Structures:  4AZL, 4B61

  • PubMed Abstract: 
  • The exopolysaccharide alginate is an important component of biofilms produced by Pseudomonas aeruginosa, a major pathogen that contributes to the demise of cystic fibrosis patients. Alginate exits the cell via the outer membrane porin AlgE. X-ray str ...

    The exopolysaccharide alginate is an important component of biofilms produced by Pseudomonas aeruginosa, a major pathogen that contributes to the demise of cystic fibrosis patients. Alginate exits the cell via the outer membrane porin AlgE. X-ray structures of several AlgE crystal forms are reported here. Whilst all share a common β-barrel constitution, they differ in the degree to which loops L2 and T8 are ordered. L2 and T8 have been identified as an extracellular gate (E-gate) and a periplasmic gate (P-gate), respectively, that reside on either side of an alginate-selectivity pore located midway through AlgE. Passage of alginate across the membrane is proposed to be regulated by the sequential opening and closing of the two gates. In one crystal form, the selectivity pore contains a bound citrate. Because citrate mimics the uronate monomers of alginate, its location is taken to highlight a route through AlgE taken by alginate as it crosses the pore. Docking and molecular-dynamics simulations support and extend the proposed transport mechanism. Specifically, the P-gate and E-gate are flexible and move between open and closed states. Citrate can leave the selectivity pore bidirectionally. Alginate docks stably in a linear conformation through the open pore. To translate across the pore, a force is required that presumably is provided by the alginate-synthesis machinery. Accessing the open pore is facilitated by complex formation between AlgE and the periplasmic protein AlgK. Alginate can thread through a continuous pore in the complex, suggesting that AlgK pre-orients newly synthesized exopolysaccharide for delivery to AlgE.


    Organizational Affiliation

    Schools of Medicine and Biochemistry and Immunology, Trinity College, Dublin, Ireland.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ALGINATE PRODUCTION PROTEIN ALGE
A
458Pseudomonas aeruginosa (strain ATCC 15692 / PAO1 / 1C / PRS 101 / LMG 12228)Gene Names: algE (alg76)
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: BETA-BARREL
Sub Group: 
Beta-Barrel Membrane Proteins: Monomeric/Dimeric
Protein: 
AlgE alginate export protein
Find proteins for P18895 (Pseudomonas aeruginosa (strain ATCC 15692 / PAO1 / 1C / PRS 101 / LMG 12228))
Go to UniProtKB:  P18895
Small Molecules
Ligands 7 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
78M
Query on 78M

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A
(2S)-2,3-DIHYDROXYPROPYL(7Z)-PENTADEC-7-ENOATE
7.8 MONOACYLGLYCEROL
C18 H34 O4
BJMLBVHMHXYQFS-JJEJIETFSA-N
 Ligand Interaction
NA
Query on NA

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A
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
78N
Query on 78N

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A
(2R)-2,3-DIHYDROXYPROPYL(7Z)-PENTADEC-7-ENOATE
7.8 MONOACYLGLYCEROL (2R)
C18 H34 O4
BJMLBVHMHXYQFS-XZVRFQMRSA-N
 Ligand Interaction
PE5
Query on PE5

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A
3,6,9,12,15,18,21,24-OCTAOXAHEXACOSAN-1-OL
2-(2-{2-[2-(2-{2-[2-(2-ETHOXY-ETHOXY)-ETHOXY]-ETHOXY}-ETHOXY)-ETHOXY]-ETHOXY}-ETHOXY)-ETHANOL, POLYETHYLENE GLYCOL PEG400
C18 H38 O9
CUDPPTPIUWYGFI-UHFFFAOYSA-N
 Ligand Interaction
CA
Query on CA

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A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
LDA
Query on LDA

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A
LAURYL DIMETHYLAMINE-N-OXIDE
C14 H31 N O
SYELZBGXAIXKHU-UHFFFAOYSA-N
 Ligand Interaction
FLC
Query on FLC

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A
CITRATE ANION
C6 H5 O7
KRKNYBCHXYNGOX-UHFFFAOYSA-K
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.897 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.163 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 57.253α = 90.00
b = 74.416β = 101.56
c = 115.529γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
SCALEPACKdata scaling
PHENIXrefinement
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-02-06
    Type: Initial release
  • Version 1.1: 2014-07-30
    Type: Database references
  • Version 1.2: 2014-08-06
    Type: Database references
  • Version 1.3: 2014-08-13
    Type: Database references
  • Version 1.4: 2015-09-30
    Type: Database references