Experimental Data Snapshot

  • Resolution: 2.60 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.226 
  • R-Value Observed: 0.226 

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This is version 2.0 of the entry. See complete history


Crystal structures of various maltooligosaccharides bound to maltoporin reveal a specific sugar translocation pathway.

Dutzler, R.Wang, Y.F.Rizkallah, P.J.Rosenbusch, J.P.Schirmer, T.

(1996) Structure 4: 127-134

  • DOI: https://doi.org/10.1016/s0969-2126(96)00016-0
  • Primary Citation of Related Structures:  
    1MPM, 1MPN, 1MPO

  • PubMed Abstract: 

    Maltoporin (which is encoded by the lamB gene) facilitates the translocation of maltodextrins across the outer membrane of E. coli. In particular, it is indispensable for the transport of long maltooligosaccharides, as these do not pass through non-specific porins. An understanding of this intriguing capability requires elucidation of the structural basis. The crystal structures of maltoporin in complex with maltose, maltotriose and maltohexaose reveal an extended binding site within the maltoporin channel. The maltooligosaccharides are in apolar van der Waals contact with the 'greasy slide', a hydrophobic path that is composed of aromatic residues and located at the channel lining. At the constriction of the channel the sugars are tightly surrounded by protein side chains and form an extensive hydrogen-bonding network with ionizable amino-acid residues. Hydrophobic interactions with the greasy slide guide the sugar into and through the channel constriction. The glucosyl-binding subsites at the channel constriction confer stereospecificity to the channel along with the ability to scavenge substrate at low concentrations.

  • Organizational Affiliation

    Department of Structural Biology, Biozentrum, University of Basel, CH-4056 Basel, Switzerland.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C
421Escherichia coliMutation(s): 0 
Membrane Entity: Yes 
Find proteins for P02943 (Escherichia coli (strain K12))
Explore P02943 
Go to UniProtKB:  P02943
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02943
Sequence Annotations
  • Reference Sequence


Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
D, E, F, G, H
D, E, F, G, H, I
Glycosylation Resources
GlyTouCan:  G66120GK
GlyCosmos:  G66120GK
Experimental Data & Validation

Experimental Data

  • Resolution: 2.60 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.226 
  • R-Value Observed: 0.226 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 129.8α = 90
b = 211.7β = 90
c = 218.2γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
X-PLORmodel building

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1997-03-12
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2015-11-25
    Changes: Database references
  • Version 1.4: 2017-03-15
    Changes: Derived calculations
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Derived calculations, Structure summary