Experimental Data Snapshot

  • Resolution: 2.40 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.195 

Starting Model: experimental
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This is version 2.1 of the entry. See complete history


Channel specificity: structural basis for sugar discrimination and differential flux rates in maltoporin.

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

(1997) J Mol Biol 272: 56-63

  • DOI: https://doi.org/10.1006/jmbi.1997.1224
  • Primary Citation of Related Structures:  
    1AF6, 1MPQ

  • PubMed Abstract: 

    Maltoporin (LamB) facilitates the diffusion of maltodextrins across the outer membrane of E. coli. The structural basis for the specificity of the channel is investigated by X-ray structure analysis of maltoporin in complex with the disaccharides sucrose, trehalose, and melibiose. The sucrose complex, determined to 2.4 A resolution, shows that the glucosyl moiety is partly inserted into the channel constriction, while the bulky fructosyl residue appears to be hindered to enter the constriction, thus interfering with its further translocation. One of the glucosyl moieties of trehalose is found in a similar position as the glucosyl moiety of sucrose, whereas melibiose appears disordered when bound to maltoporin. A comparison with the previously reported maltoporin-maltose complex sheds light on the basis for sugar discrimination, and explains the different permeation rates observed for the saccharides.

  • Organizational Affiliation

    Department of Microbiology, Biozentrum, University of Basel, Basel, CH-4056, Switzerland.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C
421Escherichia coliMutation(s): 0 
Gene Names: LAMB
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
Glycosylation Resources
GlyTouCan:  G05551OP
GlyCosmos:  G05551OP
Biologically Interesting Molecules (External Reference) 1 Unique
Experimental Data & Validation

Experimental Data

  • Resolution: 2.40 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.195 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 129.66α = 90
b = 211.51β = 90
c = 217.91γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
ROTAVATAdata reduction
CCP4model building
CCP4data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1998-03-25
    Type: Initial release
  • Version 1.1: 2008-03-03
    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: Advisory, Atomic model, Data collection, Derived calculations, Structure summary
  • Version 2.1: 2023-08-02
    Changes: Database references, Refinement description, Structure summary