1CA2 | pdb_00001ca2

REFINED STRUCTURE OF HUMAN CARBONIC ANHYDRASE II AT 2.0 ANGSTROMS RESOLUTION

• PDB DOI: https://doi.org/10.2210/pdb1CA2/pdb
• Entry: 1CA2 supersedes: 1CAC

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


• Deposited: 1989-02-06 Released: 1990-01-15 
• Deposition Author(s): Eriksson, A.E., Jones, T.A., Liljas, A.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å

Literature

Refined structure of human carbonic anhydrase II at 2.0 A resolution.

Eriksson, A.E., Jones, T.A., Liljas, A.

(1988) Proteins 4: 274-282

• PubMed: 3151019 
• DOI: https://doi.org/10.1002/prot.340040406
• Primary Citation Related Structures: 
  1CA2, 4CAC, 5CAC


• PubMed Abstract: 
  

  The structure of human erythrocytic carbonic anhydrase II has been refined by constrained and restrained structure-factor least-squares refinement at 2.0 A resolution. The conventional crystallographic R value is 17.3%. Of 167 solvent molecules associated with the protein, four are buried and stabilize secondary structure elements. The zinc ion is ligated to three histidyl residues and one water molecule in a nearly tetrahedral geometry. In addition to the zinc-bound water, seven more water molecules are identified in the active site. Assuming that Glu-106 is deprotonated at pH 8.5, some of the hydrogen bond donor-acceptor relations in the active site can be assigned and are described here in detail. The O gamma 1 atom of Thr-199 donates its proton to the O epsilon 1 atom of Glu-106 and can function as a hydrogen bond acceptor only in additional hydrogen bonds.

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Organizational Affiliation: 
• Department of Molecular Biology, Biomedical Center, Uppsala, Sweden.

Biological Assembly 1  

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

Biological assembly 1 assigned by authors.

Macromolecule Content 

• Total Structure Weight: 29.22 kDa 
• Atom Count: 2,207 
• Modeled Residue Count: 256 
• Deposited Residue Count: 259 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
CARBONIC ANHYDRASE II	A	259	Homo sapiens	Mutation(s): 0  EC: 4.2.1.1 (PDB Primary Data), 4.2.1.69 (UniProt)
UniProt & NIH Common Fund Data Resources
Find proteins for P00918 (Homo sapiens) Explore P00918  Go to UniProtKB:  P00918
PHAROS:  P00918 GTEx:  ENSG00000104267

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
ZN	B [auth A]	ZINC ION Zn PTFCDOFLOPIGGS-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å

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
PROLSQ	refinement

Structure Validation

Entry History 

Deposition Data

• Released Date: 1990-01-15 
Deposition Author(s): Eriksson, A.E., Jones, T.A., Liljas, A.
• This entry supersedes: 1CAC

Revision History  

• Version 1.0: 1990-01-15
  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: 2017-11-29
  Changes: Derived calculations, Other
• Version 1.4: 2024-02-07
  Changes: Data collection, Database references, Derived calculations