4AFK

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


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.163 
  • R-Value Observed: 0.166 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.7 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 D Biol Crystallogr 70: 2054

  • DOI: https://doi.org/10.1107/S1399004714001850
  • Primary Citation of Related Structures:  
    4AFK, 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 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:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ALGINATE PRODUCTION PROTEIN ALGE458Pseudomonas aeruginosa PAO1Mutation(s): 0 
Membrane Entity: Yes 
UniProt
Find proteins for P18895 (Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1))
Explore P18895 
Go to UniProtKB:  P18895
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP18895
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 7 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
PE5
Query on PE5

Download Ideal Coordinates CCD File 
AA [auth A],
BA [auth A]
3,6,9,12,15,18,21,24-OCTAOXAHEXACOSAN-1-OL
C18 H38 O9
CUDPPTPIUWYGFI-UHFFFAOYSA-N
78N
Query on 78N

Download Ideal Coordinates CCD File 
V [auth A],
X [auth A],
Y [auth A]
(2R)-2,3-DIHYDROXYPROPYL(7Z)-PENTADEC-7-ENOATE
C18 H34 O4
BJMLBVHMHXYQFS-XZVRFQMRSA-N
78M
Query on 78M

Download Ideal Coordinates CCD File 
U [auth A],
W [auth A],
Z [auth A]
(2S)-2,3-DIHYDROXYPROPYL(7Z)-PENTADEC-7-ENOATE
C18 H34 O4
BJMLBVHMHXYQFS-JJEJIETFSA-N
LDA
Query on LDA

Download Ideal Coordinates CCD File 
D [auth A]
E [auth A]
F [auth A]
G [auth A]
H [auth A]
D [auth A],
E [auth A],
F [auth A],
G [auth A],
H [auth A],
I [auth A],
J [auth A],
K [auth A],
L [auth A],
M [auth A],
N [auth A],
O [auth A],
P [auth A],
Q [auth A],
R [auth A]
LAURYL DIMETHYLAMINE-N-OXIDE
C14 H31 N O
SYELZBGXAIXKHU-UHFFFAOYSA-N
FLC
Query on FLC

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C [auth A]CITRATE ANION
C6 H5 O7
KRKNYBCHXYNGOX-UHFFFAOYSA-K
CA
Query on CA

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B [auth A]CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
NA
Query on NA

Download Ideal Coordinates CCD File 
S [auth A],
T [auth A]
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.163 
  • R-Value Observed: 0.166 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 57.253α = 90
b = 74.416β = 101.56
c = 115.529γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data reduction
SCALEPACKdata scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-02-06
    Type: Initial release
  • Version 1.1: 2014-07-30
    Changes: Database references
  • Version 1.2: 2014-08-06
    Changes: Database references
  • Version 1.3: 2014-08-13
    Changes: Database references
  • Version 1.4: 2015-09-30
    Changes: Database references
  • Version 1.5: 2019-05-22
    Changes: Data collection, Experimental preparation, Other
  • Version 1.6: 2023-03-29
    Changes: Database references, Derived calculations, Other, Structure summary
  • Version 1.7: 2024-02-07
    Changes: Data collection, Refinement description