1G0E

SITE-SPECIFIC MUTANT (HIS64 REPLACED WITH ALA) OF HUMAN CARBONIC ANHYDRASE II COMPLEXED WITH 4-METHYLIMIDAZOLE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.200 
  • R-Value Work: 0.179 
  • R-Value Observed: 0.179 

wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

Structural and kinetic analysis of the chemical rescue of the proton transfer function of carbonic anhydrase II.

Duda, D.Tu, C.Qian, M.Laipis, P.Agbandje-McKenna, M.Silverman, D.N.McKenna, R.

(2001) Biochemistry 40: 1741-1748

  • DOI: https://doi.org/10.1021/bi002295z
  • Primary Citation of Related Structures:  
    1G0E, 1G0F

  • PubMed Abstract: 
  • Histidine 64 in human carbonic anhydrase II (HCA II) functions in the catalytic pathway of CO(2) hydration as a shuttle to transfer protons between the zinc-bound water and bulk water. Catalysis of the exchange of (18)O between CO(2) and water, measured by mass spectrometry, is dependent on this proton transfer and was decreased more than 10-fold for H64A HCA II compared with wild-type HCA II ...

    Histidine 64 in human carbonic anhydrase II (HCA II) functions in the catalytic pathway of CO(2) hydration as a shuttle to transfer protons between the zinc-bound water and bulk water. Catalysis of the exchange of (18)O between CO(2) and water, measured by mass spectrometry, is dependent on this proton transfer and was decreased more than 10-fold for H64A HCA II compared with wild-type HCA II. The loss of catalytic activity of H64A HCA II could be rescued by 4-methylimidazole (4-MI), an exogenous proton donor, in a saturable process with a maximum activity of 40% of wild-type HCA II. The crystal structure of the rescued complex at 1.6 A resolution shows 4-MI bound in the active-site cavity of H64A HCA II, through pi stacking interactions with Trp 5 and H-bonding interactions with water molecules. In this location, 4-MI is about 12 A from the zinc and approximates the observed "out" position of His 64 in the structure of the wild-type enzyme. 4-MI appears to compensate for the absence of His 64 and rescues the catalytic activity of the H64A HCA II mutant. This result strongly suggests that the out conformation of His 64 is effective in the transfer of protons between the zinc-bound solvent molecule and solution.


    Related Citations: 
    • Structure of Native and Apo Carbonic Anhydrase II and Structure of Some of its Anion-ligand Complexes.
      Hakansson, K., Carlsson, M., Svensson, L.A., Liljas, A.
      (1992) J Mol Biol 227: 1192

    Organizational Affiliation

    Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CARBONIC ANHYDRASE II260Homo sapiensMutation(s): 1 
Gene Names: CA2
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
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00918
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HG
Query on HG

Download Ideal Coordinates CCD File 
C [auth A]MERCURY (II) ION
Hg
BQPIGGFYSBELGY-UHFFFAOYSA-N
 Ligand Interaction
4MZ
Query on 4MZ

Download Ideal Coordinates CCD File 
D [auth A]4-METHYLIMIDAZOLE
C4 H6 N2
XLSZMDLNRCVEIJ-UHFFFAOYSA-N
 Ligand Interaction
ZN
Query on ZN

Download Ideal Coordinates CCD File 
B [auth A]ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.200 
  • R-Value Work: 0.179 
  • R-Value Observed: 0.179 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 42.142α = 90
b = 41.49β = 104.28
c = 72.063γ = 90
Software Package:
Software NamePurpose
CNSrefinement
SCALEPACKdata scaling
CNSphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2000-10-18
    Type: Initial release
  • Version 1.1: 2007-10-16
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-04
    Changes: Refinement description
  • Version 1.4: 2021-11-03
    Changes: Database references, Derived calculations