Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

Global Symmetry: Cyclic - C3  (3D View)
Global Stoichiometry: Homo 3-mer - A3 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 143.86 kDa 
• Atom Count: 10155 
• Modelled Residue Count: 1263 
• Deposited Residue Count: 1263 
• Unique protein chains: 1

1MPN

MALTOPORIN MALTOTRIOSE COMPLEX

• DOI: 10.2210/pdb1MPN/pdb

• Classification: MEMBRANE PROTEIN
• Organism(s): Escherichia coli
• Mutation(s): No 


• Deposited: 1996-01-11 Released: 1997-03-12 
• Deposition Author(s): Dutzler, R., Schirmer, T.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 3.20 Å
• R-Value Free: 0.231 
• R-Value Work: 0.218 
• R-Value Observed: 0.218 

Literature

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

• PubMed: 8805519 
• DOI: 10.1016/s0969-2126(96)00016-0
• Primary Citation of Related Structures:  
  1MPO, 1MPN, 1MPM


• 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.

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Related Citations: 

• Structural Basis for Sugar Translocation Through Maltoporin Channels at 3.1 A Resolution
  Schirmer, T., Keller, T.A., Wang, Y.F., Rosenbusch, J.P.
  (1995) Science 267: 512

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Organizational Affiliation: 

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

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
MALTOPORIN	A, B, C	421	Escherichia coli	Mutation(s): 0
Membrane protein Mpstruc	Group:  TRANSMEMBRANE PROTEINS: BETA-BARREL		Sub Group:  Beta-Barrel Membrane Proteins: Porins and Relatives	Protein:  LamB Maltoporin in complex with maltose
Find proteins for P02943 (Escherichia coli (strain K12)) Explore P02943  Go to UniProtKB:  P02943

Oligosaccharides

Help

Entity ID: 2
Molecule	Chains	Chain Length	2D Diagram	Glycosylation
alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose	D, E, F	3		N/A

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
MG	A, B, C	MAGNESIUM ION Mg JLVVSXFLKOJNIY-UHFFFAOYSA-N

Biologically Interesting Molecules (External Reference) 1 Unique

Entity ID: 2
ID	Chains	Name	Type/Class	2D Diagram	3D Interactions
PRD_900009	D, E, F	alpha-maltotriose	Oligosaccharide /  Nutrient		--

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 3.20 Å
• R-Value Free: 0.231 
• R-Value Work: 0.218 
• R-Value Observed: 0.218 
• Space Group: C 2 2 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 131.9	α = 90
b = 214.8	β = 90
c = 220.2	γ = 90

Software Package:

Software Name	Purpose
MOSFLM	data reduction
X-PLOR	model building
X-PLOR	refinement
X-PLOR	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 1996-01-11 
• Released Date: 1997-03-12 
Deposition Author(s): Dutzler, R., Schirmer, T.

Revision History  

• 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 2.0: 2020-07-29
  Type: Remediation
  Reason: Carbohydrate remediation
  Changes: Advisory, Atomic model, Data collection, Derived calculations, Structure summary