Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

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

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 60289.71 
• Atom Count: 4195 
• Residue Count: 526 
• Unique protein chains: 1

1JD0

CRYSTAL STRUCTURE OF THE EXTRACELLULAR DOMAIN OF HUMAN CARBONIC ANHYDRASE XII COMPLEXED WITH ACETAZOLAMIDE

• DOI: 10.2210/pdb1JD0/pdb

• Classification: LYASE
• Organism(s): Homo sapiens
• Expression System: Escherichia coli BL21(DE3)


• Deposited: 2001-06-11 Released: 2001-08-17 
• Deposition Author(s): Whittington, D.A., Waheed, A., Ulmasov, B., Shah, G.N., Grubb, J.H., Sly, W.S., Christianson, D.W.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.5 Å
• R-Value Free: 0.207 
• R-Value Work: 0.190 

Literature

Crystal structure of the dimeric extracellular domain of human carbonic anhydrase XII, a bitopic membrane protein overexpressed in certain cancer tumor cells.

Whittington, D.A., Waheed, A., Ulmasov, B., Shah, G.N., Grubb, J.H., Sly, W.S., Christianson, D.W.

(2001) Proc.Natl.Acad.Sci.USA 98: 9545-9550

• PubMed: 11493685 
• DOI: 10.1073/pnas.161301298
• Primary Citation of Related Structures:  
  1JCZ


• PubMed Abstract: 
  

Overexpression of the zinc enzyme carbonic anhydrase (CA; EC ) XII is observed in certain human cancers. This bitopic membrane protein contains an N-terminal extracellular catalytic domain, a membrane-spanning alpha-helix, and a small intracellular C-terminal domain. We have determined the three-dimensional structure of the extracellular catalytic domain of human CA XII by x-ray crystallographic methods at 1.55-A resolution. The structure reveals a prototypical CA fold; however, two CA XII domains associate to form an isologous dimer, an observation that is confirmed by studies of the enzyme in solution. The identification of signature GXXXG and GXXXS motifs in the transmembrane sequence that facilitate helix-helix association is additionally consistent with dimeric architecture. The dimer interface is situated so that the active site clefts of each monomer are clearly exposed on one face of the dimer, and the C termini are located together on the opposite face of the dimer to facilitate membrane interaction. The amino acid composition of the active-site cleft closely resembles that of the other CA isozymes in the immediate vicinity of the catalytic zinc ion, but differs in the region of the nearby alpha-helical "130's segment." The structure of the CA XII-acetazolamide complex is also reported at 1.50-A resolution, and prospects for the design of CA XII-specific inhibitors of possible chemotherapeutic value are discussed.

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Organizational Affiliation: 

Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA.

Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
CARBONIC ANHYDRASE XII	A, B	263	Homo sapiens	Mutation(s): 0  Gene Names: CA12 EC: 4.2.1.1
Find proteins for O43570 (Homo sapiens) Go to Gene View: CA12 Go to UniProtKB:  O43570

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram & Interactions
ZN	A, B	ZINC ION Zn PTFCDOFLOPIGGS-UHFFFAOYSA-N
AZM	A, B	5-ACETAMIDO-1,3,4-THIADIAZOLE-2-SULFONAMIDE C4 H6 N4 O3 S2 BZKPWHYZMXOIDC-UHFFFAOYSA-N

External Ligand Annotations
ID	Binding Affinity (Sequence Identity %)
AZM	Kd: 25 - 330 nM (99) BINDINGDB
AZM	Ki: 2.5 - 6 nM (99) BINDINGDB
AZM	IC50: 60 - 88 nM (99) BINDINGDB
AZM	Ki: 5.7 nM PDBBIND

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.5 Å
• R-Value Free: 0.207 
• R-Value Work: 0.190 
• Space Group: C 1 2 1

Unit Cell:

Length (Å)	Angle (°)
a = 146.875	α = 90.00
b = 45.080	β = 93.98
c = 85.232	γ = 90.00

Software Package:

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

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2001-06-11 
• Released Date: 2001-08-17 
• Deposition Author(s): Whittington, D.A., Waheed, A., Ulmasov, B., Shah, G.N., Grubb, J.H., Sly, W.S., Christianson, D.W.

Revision History 

• Version 1.0: 2001-08-17
  Type: Initial release
• Version 1.1: 2008-04-27
  Type: Version format compliance
• Version 1.2: 2011-07-13
  Type: Version format compliance
• Version 1.3: 2011-11-16
  Type: Atomic model