1Y3N

Structure of AlgQ1, alginate-binding protein, complexed with an alginate disaccharide


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.197 

wwPDB Validation 3D Report Full Report



Literature

Direct Evidence for Sphingomonas sp. A1 Periplasmic Proteins as Macromolecule-Binding Proteins Associated with the ABC Transporter: Molecular Insights into Alginate Transport in the Periplasm(,)

Momma, K.Mishima, Y.Hashimoto, W.Mikami, B.Murata, K.

(2005) Biochemistry 44: 5053-5064

  • DOI: 10.1021/bi047781r
  • Primary Citation of Related Structures:  
    1Y3Q, 1Y3P, 1Y3N

  • PubMed Abstract: 
  • A Gram-negative bacterium, Sphingomonas sp. A1, has a macromolecule (alginate) import system consisting of a pit on the cell surface and an alginate-specific ATP-binding cassette importer in the inner membrane. Transport of alginate from the pit to t ...

    A Gram-negative bacterium, Sphingomonas sp. A1, has a macromolecule (alginate) import system consisting of a pit on the cell surface and an alginate-specific ATP-binding cassette importer in the inner membrane. Transport of alginate from the pit to the ABC importer is probably mediated by two periplasmic binding protein homologues (AlgQ1 and AlgQ2). Here we describe characteristics of binding of AlgQ1 and AlgQ2 to alginate and its oligosaccharides through surface plasmon resonance biosensor analysis, UV absorption difference spectroscopy, and X-ray crystallography. Both AlgQ1 and AlgQ2 were inducibly expressed in the periplasm of alginate-grown cells of strain A1. Biosensor analysis indicated that both proteins specifically bind alginate with a high degree of polymerization (>100) and that dissociation constants for alginate with an average molecular mass of 26 kDa are 2.3 x 10(-)(7) M for AlgQ1 and 1.5 x 10(-)(7) M for AlgQ2. An in vitro ATPase assay using the membrane complex, including the alginate ABC importer, suggested that both alginate-bound forms of AlgQ1 and AlgQ2 are closely associated with the importer. X-ray crystallography showed that AlgQ1 consisted of two domains separated by a deep cleft that binds alginate oligosaccharides through a conformational change in the two domains. These results directly show that alginate-binding proteins play an important role in the efficient transport of alginate macromolecules with different degrees of polymerization in the periplasm.


    Organizational Affiliation

    Laboratory of Basic and Applied Molecular Biotechnology, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
AlgQ1A490Sphingomonas sp. A1Mutation(s): 0 
Find proteins for Q9KWT6 (Sphingomonas sp)
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Go to UniProtKB:  Q9KWT6
Protein Feature View
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  • Reference Sequence
Oligosaccharides

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Entity ID: 2
MoleculeChainsChain Length2D Diagram Glycosylation3D Interactions
beta-D-mannopyranuronic acid-(1-4)-alpha-D-mannopyranuronic acid
B
2 N/A Oligosaccharides Interaction
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.197 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 58.434α = 90
b = 67.788β = 95.31
c = 62.811γ = 90
Software Package:
Software NamePurpose
CNSrefinement
d*TREKdata scaling
CNSphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-04-12
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Source and taxonomy, Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Derived calculations, Structure summary