Biological Assembly 1  

 3D View: Structure | Ligand Interaction

Standalone Viewers  
Protein Workshop | Ligand Explorer

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A 

Biological assembly 1 assigned by authors.

Biological Assembly 2  

 3D View: Structure | Ligand Interaction

Standalone Viewers  
Protein Workshop | Ligand Explorer

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A 

Biological assembly 2 assigned by authors.

Macromolecule Content

• Total Structure Weight: 93686.32 
• Atom Count: 6626 
• Residue Count: 834 
• Unique protein chains: 1

1PV7

Crystal structure of lactose permease with TDG

• DOI: 10.2210/pdb1PV7/pdb

• Classification: TRANSPORT PROTEIN
• Organism(s): Escherichia coli (strain K12)
• Expression System: Cricetulus griseus
• Mutation(s): 1 


• Deposited: 2003-06-26 Released: 2003-08-12 
• Deposition Author(s): Abramson, J., Smirnova, I., Kasho, V., Verner, G., Kaback, H.R., Iwata, S.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 3.6 Å
• R-Value Free: 0.296 
• R-Value Work: 0.271 

Literature

Structure and mechanism of the lactose permease of Escherichia coli

Abramson, J., Smirnova, I., Kasho, V., Verner, G., Kaback, H.R., Iwata, S.

(2003) SCIENCE 301: 610-615

• PubMed: 12893935 
• DOI: 10.1126/science.1088196
• Primary Citation of Related Structures:  
  1PV6


• PubMed Abstract: 
  

Membrane transport proteins that transduce free energy stored in electrochemical ion gradients into a concentration gradient are a major class of membrane proteins. We report the crystal structure at 3.5 angstroms of the Escherichia coli lactose permease, an intensively studied member of the major facilitator superfamily of transporters. The molecule is composed of N- and C-terminal domains, each with six transmembrane helices, symmetrically positioned within the permease. A large internal hydrophilic cavity open to the cytoplasmic side represents the inward-facing conformation of the transporter. The structure with a bound lactose homolog, beta-D-galactopyranosyl-1-thio-beta-D-galactopyranoside, reveals the sugar-binding site in the cavity, and residues that play major roles in substrate recognition and proton translocation are identified. We propose a possible mechanism for lactose/proton symport (co-transport) consistent with both the structure and a large body of experimental data.

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Organizational Affiliation: 

Department of Biological Sciences, Imperial College London, London SW7 2AZ, UK.

Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
Lactose permease	A, B	417	Escherichia coli (strain K12)	Mutation(s): 1  Gene Names: lacY
Membrane protein mpstruc	Group:  TRANSMEMBRANE PROTEINS: ALPHA-HELICAL		Sub Group:  Major Facilitator Superfamily (MFS) Transporters	Protein:  LacY Lactose Permease Transporter (C154G mutant)
Find proteins for P02920 (Escherichia coli (strain K12)) Go to UniProtKB:  P02920

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram & Interactions
TDG	A, B	THIODIGALACTOSIDE C12 H22 O10 S SYKYBMOFPMXDRQ-ZFDCCPEWSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 3.6 Å
• R-Value Free: 0.296 
• R-Value Work: 0.271 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length (Å)	Angle (°)
a = 101.351	α = 90.00
b = 125.845	β = 90.00
c = 188.118	γ = 90.00

Software Package:

Software Name	Purpose
DENZO	data reduction
CNS	refinement
SCALEPACK	data scaling
SHARP	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2003-06-26 
• Released Date: 2003-08-12 
• Deposition Author(s): Abramson, J., Smirnova, I., Kasho, V., Verner, G., Kaback, H.R., Iwata, S.

Revision History 

• Version 1.0: 2003-08-12
  Type: Initial release
• Version 1.1: 2008-04-29
  Type: Version format compliance
• Version 1.2: 2011-07-13
  Type: Version format compliance