1MPM

MALTOPORIN MALTOSE COMPLEX

• PDB DOI: https://doi.org/10.2210/pdb1MPM/pdb

• Classification: MEMBRANE PROTEIN
• Organism(s): Escherichia coli
• Mutation(s): No 
• Membrane Protein: Yes  PDBTMMemProtMDmpstruc


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

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: 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.

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Organizational Affiliation: 

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

Biological Assembly 1  

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

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

Macromolecule Content

• Total Structure Weight: 144.4 kDa 
• Atom Count: 10,662 
• Modelled Residue Count: 1,263 
• Deposited Residue Count: 1,263 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
MALTOPORIN	A, B, C	421	Escherichia coli	Mutation(s): 0  Membrane Entity: Yes
UniProt
Find proteins for P02943 (Escherichia coli (strain K12)) Explore P02943  Go to UniProtKB:  P02943

Oligosaccharides

Help

Entity ID: 2
Molecule	Chains	Length	2D Diagram	Glycosylation	3D Interactions
alpha-D-glucopyranose-(1-4)-beta-D-glucopyranose	D, E, F, G, H, I	2		N/A
Glycosylation Resources
GlyTouCan:  G66120GK GlyCosmos:  G66120GK

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
MG	J [auth A], K [auth A], L [auth B]	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_900018	D, E, F, G, H, I	beta-maltose	Oligosaccharide / Nutrient

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• 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 = 129.8	α = 90
b = 211.7	β = 90
c = 218.2	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

• 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 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