Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 29.31 kDa 
• Atom Count: 2286 
• Residue Count: 258 
• Unique protein chains: 1

1CAJ

STRUCTURAL ANALYSIS OF THE ZINC HYDROXIDE-THR 199-GLU 106 HYDROGEN BONDING NETWORK IN HUMAN CARBONIC ANHYDRASE II

• DOI: 10.2210/pdb1CAJ/pdb

• Classification: LYASE(OXO-ACID)
• Organism(s): Homo sapiens
• Mutation(s): No 


• Deposited: 1992-09-17 Released: 1993-10-31 
• Deposition Author(s): Xue, Y., Liljas, A., Jonsson, B.-H., Lindskog, S.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.90 Å
• R-Value Observed: 0.151 

Literature

Structural analysis of the zinc hydroxide-Thr-199-Glu-106 hydrogen-bond network in human carbonic anhydrase II.

Xue, Y., Liljas, A., Jonsson, B.H., Lindskog, S.

(1993) Proteins 17: 93-106

• PubMed: 7901850 
• DOI: 10.1002/prot.340170112
• Structures With Same Primary Citation


• PubMed Abstract: 
  

The significance of the zinc hydroxide-Thr-199-Glu-106 hydrogen-bond network in the active site of human carbonic anhydrase II has been examined by X-ray crystallographic analyses of site-specific mutants. Mutants with Ala-199 and Ala-106 or Gln-106 have low catalytic activities, while a mutant with Asp-106 has almost full CO2 hydration activity. The structures of these four mutants, as well as that of the bicarbonate complex of the mutant with Ala-199, have been determined at 1.7 to 2.2 A resolution. Removal of the gamma atoms of residue 199 leads to a distorted tetrahedral geometry at the zinc ion, and a catalytically important zinc-bound water molecule has moved towards Glu-106. In the bicarbonate complex of the mutant with Ala-199 one oxygen atom from bicarbonate binds to zinc without displacing this water molecule. Tetrahedral coordination geometries are retained in the mutants at position 106. The mutants with Ala-106 and Gln-106 have a zinc-bound sulfate ion, whereas this sulfate site is only partially occupied in the mutant with Asp-106. The hydrogen-bond network seems to be "reversed" in the mutants with Ala-106 and Gln-106. The network is preserved as in native enzyme in the mutant with Asp-106 but the side chain of Asp-106 is more extended than that of Glu-106 in the native enzyme. These results illustrate the importance of Glu-106 and Thr-199 for controlling the precise coordination geometry of the zinc ion and its ligand preferences which results in an optimal orientation of a zinc-bound hydroxide ion for an attack on the CO2 substrate.

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Organizational Affiliation: 

Department of Biochemistry, University of Umeå, Sweden.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
CARBONIC ANHYDRASE II	A	259	Homo sapiens	Mutation(s): 0  Gene Names: CA2 EC: 4.2.1.1
Find proteins for P00918 (Homo sapiens) Go to UniProtKB:  P00918
NIH Common Fund Data Resources
PHAROS  P00918 GTEx  ENSG00000104267

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
SO4	A	SULFATE ION O4 S QAOWNCQODCNURD-UHFFFAOYSA-L
ZN	A	ZINC ION Zn PTFCDOFLOPIGGS-UHFFFAOYSA-N

External Ligand Annotations
ID	Binding Affinity (Sequence Identity %)
SO4	Ki:  300000000   nM  BindingDB
SO4	Ki:  89000000   nM  BindingDB
SO4	Ki:  200000000   nM  BindingDB
SO4	Ki:  183000000   nM  BindingDB

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.90 Å
• R-Value Observed: 0.151 
• Space Group: P 1 2₁ 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 42.7	α = 90
b = 41.7	β = 104.6
c = 73	γ = 90

Software Package:

Software Name	Purpose
PROFFT	refinement

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 1992-09-17 
• Released Date: 1993-10-31 
Deposition Author(s): Xue, Y., Liljas, A., Jonsson, B.-H., Lindskog, S.

Revision History 

• Version 1.0: 1993-10-31
  Type: Initial release
  
• Version 1.1: 2008-03-03
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2017-11-29
  Changes: Derived calculations, Other