1HVA

ENGINEERING THE ZINC BINDING SITE OF HUMAN CARBONIC ANHYDRASE II: STRUCTURE OF THE HIS-94-> CYS APOENZYME IN A NEW CRYSTALLINE FORM


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Work: 0.155 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Engineering the zinc binding site of human carbonic anhydrase II: structure of the His-94-->Cys apoenzyme in a new crystalline form.

Alexander, R.S.Kiefer, L.L.Fierke, C.A.Christianson, D.W.

(1993) Biochemistry 32: 1510-1518


  • PubMed Abstract: 
  • The structure of the His-94-->Cys variant of human carbonic anhydrase II (CAII) has been determined by X-ray crystallographic methods to a resolution of 2.3 A with a final crystallographic R factor of 0.155. This variant of CAII crystallizes in ortho ...

    The structure of the His-94-->Cys variant of human carbonic anhydrase II (CAII) has been determined by X-ray crystallographic methods to a resolution of 2.3 A with a final crystallographic R factor of 0.155. This variant of CAII crystallizes in orthorhombic space group P2(1)2(1)2(1) which is the first example of a new crystal form for this important zinc hydrase (the wild-type enzyme crystallizes in monoclinic space group P21 under similar crystallization conditions). Although the overall structure of the enzyme in the orthorhombic crystal form is similar to that of the wild-type protein in the monoclinic crystal form, the rms deviation of C alpha atoms between the two structures is 0.5 A. Larger structural deviations occur in regions of the protein molecule involved in crystal lattice contacts, and significant structural changes are found in the polypeptide strand containing Cys-94. Surprisingly, no electron density corresponding to a zinc ion is found in the active site of crystalline His-94-->Cys CAII, even though the stoichiometry of zinc binding to this variant in solution is confirmed by atomic absorption spectroscopy. However, the KD for zinc dissociation from the variant is increased 10(4)-fold compared with wild-type enzyme; furthermore, under the crystallization conditions of high ionic strength (1.75-2.5 M ammonium sulfate), the observed KD is increased further, which leads to zinc dissociation. Spectroscopic analysis of Co(2+)-substituted His-94-->Cys CAII indicates that the metal binds in a tetrahedral geometry with a new thiolate bond.(ABSTRACT TRUNCATED AT 250 WORDS)


    Organizational Affiliation

    Department of Chemistry, University of Pennsylvania, Philadelphia 19104-6323.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CARBONIC ANHYDRASE II
A
260Homo sapiensGene Names: CA2
EC: 4.2.1.1
Find proteins for P00918 (Homo sapiens)
Go to Gene View: CA2
Go to UniProtKB:  P00918
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Work: 0.155 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 42.400α = 90.00
b = 72.200β = 90.00
c = 75.200γ = 90.00
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
X-PLORphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1993-10-31
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance