1FQC

CRYSTAL STRUCTURE OF MALTOTRIOTOL BOUND TO CLOSED-FORM MALTODEXTRIN BINDING PROTEIN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.199 

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This is version 2.0 of the entry. See complete history


Literature

Crystal structures of the maltodextrin/maltose-binding protein complexed with reduced oligosaccharides: flexibility of tertiary structure and ligand binding.

Duan, X.Hall, J.A.Nikaido, H.Quiocho, F.A.

(2001) J Mol Biol 306: 1115-1126

  • DOI: 10.1006/jmbi.2001.4456
  • Primary Citation of Related Structures:  
    1FQC, 1FQB, 1FQA, 1FQD

  • PubMed Abstract: 
  • The structure of the maltodextrin or maltose-binding protein, an initial receptor for bacterial ABC-type active transport and chemotaxis, consists of two globular domains that are separated by a groove wherein the ligand is bound and enclosed by an inter-domain rotation ...

    The structure of the maltodextrin or maltose-binding protein, an initial receptor for bacterial ABC-type active transport and chemotaxis, consists of two globular domains that are separated by a groove wherein the ligand is bound and enclosed by an inter-domain rotation. Here, we report the determination of the crystal structures of the protein complexed with reduced maltooligosaccharides (maltotriitol and maltotetraitol) in both the "closed" and "open" forms. Although these modified sugars bind to the receptor, they are not transported by the wild-type transporter. In the closed structures, the reduced sugars are buried in the groove and bound by both domains, one domain mainly by hydrogen-bonding interactions and the other domain primarily by non-polar interactions with aromatic side-chains. In the open structures, which abrogate both cellular activities of active transport and chemotaxis because of the large separation between the two domains, the sugars are bound almost exclusively to the domain rich in aromatic residues. The binding site for the open chain glucitol residue extends to a subsite that is distinct from those for the glucose residues that were uncovered in prior structural studies of the binding of active linear maltooligosaccharides. Occupation of this subsite may also account for the inability of the reduced oligosaccharides to be transported. The structures reported here, combined with those previously determined for several other complexes with active oligosaccharides in the closed form and with cyclodextrin in the open form, revealed at least four distinct modes of ligand binding but with only one being functionally active. This versatility reflects the flexibility of the protein, from very large motions of interdomain rotation to more localized side-chain conformational changes, and adaptation by the oligosaccharides as well.


    Organizational Affiliation

    Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
MALTODEXTRIN-BINDING PROTEIN A370Escherichia coliMutation(s): 0 
Find proteins for P0AEX9 (Escherichia coli (strain K12))
Explore P0AEX9 
Go to UniProtKB:  P0AEX9
Protein Feature View
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  • Reference Sequence
Oligosaccharides

Help

Entity ID: 2
MoleculeChainsChain Length2D Diagram Glycosylation3D Interactions
alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-D-glucose
B
3 N/A Oligosaccharides Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.199 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 105α = 90
b = 68.1β = 112.7
c = 57.5γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
DENZOdata reduction
SCALEPACKdata scaling
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-03-14
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Structure summary