Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

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

Macromolecule Content

• Total Structure Weight: 38.66 kDa 
• Atom Count: 2490 
• Modelled Residue Count: 308 
• Deposited Residue Count: 332 
• Unique protein chains: 1

3ZUX

Crystal structure of a bacterial homologue of the bile acid sodium symporter ASBT.

• DOI: 10.2210/pdb3ZUX/pdb

• Classification: TRANSPORT PROTEIN
• Organism(s): Neisseria meningitidis
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): Yes 


• Deposited: 2011-07-21 Released: 2011-10-12 
• Deposition Author(s): Hu, N.-J., Iwata, S., Cameron, A.D., Drew, D.

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.20 Å
• R-Value Free: 0.229 
• R-Value Work: 0.197 
• R-Value Observed: 0.199 

Literature

Crystal Structure of a Bacterial Homologue of the Bile Acid Sodium Symporter Asbt.

Hu, N.-J., Iwata, S., Cameron, A.D., Drew, D.

(2011) Nature 478: 408

• PubMed: 21976025 
• DOI: 10.1038/nature10450
• Primary Citation of Related Structures:  
  3ZUX, 3ZUY


• PubMed Abstract: 
  

High cholesterol levels greatly increase the risk of cardiovascular disease. About 50 per cent of cholesterol is eliminated from the body by its conversion into bile acids. However, bile acids released from the bile duct are constantly recycled, being reabsorbed in the intestine by the apical sodium-dependent bile acid transporter (ASBT, also known as SLC10A2). It has been shown in animal models that plasma cholesterol levels are considerably lowered by specific inhibitors of ASBT, and ASBT is thus a target for hypercholesterolaemia drugs. Here we report the crystal structure of a bacterial homologue of ASBT from Neisseria meningitidis (ASBT(NM)) at 2.2 Å. ASBT(NM) contains two inverted structural repeats of five transmembrane helices. A core domain of six helices harbours two sodium ions, and the remaining four helices pack in a row to form a flat, 'panel'-like domain. Overall, the architecture of the protein is remarkably similar to the sodium/proton antiporter NhaA, despite having no detectable sequence homology. The ASBT(NM) structure was captured with the substrate taurocholate present, bound between the core and panel domains in a large, inward-facing, hydrophobic cavity. Residues near this cavity have been shown to affect the binding of specific inhibitors of human ASBT. The position of the taurocholate molecule, together with the molecular architecture, suggests the rudiments of a possible transport mechanism.

---

Organizational Affiliation: 

Division of Molecular Biosciences, Imperial College London, London SW7 2AZ, UK.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
TRANSPORTER	A	332	Neisseria meningitidis	Mutation(s): 1
Membrane protein Mpstruc	Group:  TRANSMEMBRANE PROTEINS: ALPHA-HELICAL		Sub Group:  Apical Sodium-Dependent Bile Acid Transporters (ASBT)	Protein:  Bacterial homologue of ASBT (ASBTNM) with bound taurocholate
Find proteins for Q9K0A9 (Neisseria meningitidis serogroup B (strain MC58)) Explore Q9K0A9  Go to UniProtKB:  Q9K0A9

Small Molecules

Ligands 5 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
PTY	J [auth A], K [auth A]	PHOSPHATIDYLETHANOLAMINE C40 H80 N O8 P NJGIRBISCGPRPF-KXQOOQHDSA-N
TCH	E [auth A], F [auth A]	TAUROCHOLIC ACID C26 H45 N O7 S WBWWGRHZICKQGZ-HZAMXZRMSA-N
LDA	G [auth A], H [auth A], I [auth A], L [auth A], M [auth A]	LAURYL DIMETHYLAMINE-N-OXIDE C14 H31 N O SYELZBGXAIXKHU-UHFFFAOYSA-N
HG	D [auth A]	MERCURY (II) ION Hg BQPIGGFYSBELGY-UHFFFAOYSA-N
NA	B [auth A], C [auth A]	SODIUM ION Na FKNQFGJONOIPTF-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.20 Å
• R-Value Free: 0.229 
• R-Value Work: 0.197 
• R-Value Observed: 0.199 
• Space Group: P 4₁ 2 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 73.33	α = 90
b = 73.33	β = 90
c = 163.52	γ = 90

Software Package:

Software Name	Purpose
BUSTER	refinement
MOSFLM	data reduction
SCALA	data scaling
SHARP	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2011-07-21 
• Released Date: 2011-10-12 
Deposition Author(s): Hu, N.-J., Iwata, S., Cameron, A.D., Drew, D.

Revision History  

• Version 1.0: 2011-10-12
  Type: Initial release
  
• Version 1.1: 2011-10-26
  Changes: Database references, Structure summary