2FNK

Activation of Human Carbonic Anhydrase II by exogenous proton donors


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.204 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Location of binding sites in small molecule rescue of human carbonic anhydrase II.

Bhatt, D.Fisher, S.Z.Tu, C.McKenna, R.Silverman, D.N.

(2007) Biophys.J. 92: 562-570

  • DOI: 10.1529/biophysj.106.093203
  • Primary Citation of Related Structures:  2FNM, 2FNN

  • PubMed Abstract: 
  • Small molecule rescue of mutant forms of human carbonic anhydrase II (HCA II) occurs by participation of exogenous donors/acceptors in the proton transfer pathway between the zinc-bound water and solution. To examine more thoroughly the energetics of ...

    Small molecule rescue of mutant forms of human carbonic anhydrase II (HCA II) occurs by participation of exogenous donors/acceptors in the proton transfer pathway between the zinc-bound water and solution. To examine more thoroughly the energetics of this activation, we have constructed a mutant, H64W HCA II, which we have shown is activated by 4-methylimidazole (4-MI) by a mechanism involving the binding of 4-MI to the side chain of Trp-64 approximately 8 A from the zinc. A series of experiments are consistent with the activation of H64W HCA II by the interaction of imidazole and pyridine derivatives as exogenous proton donors with the indole ring of Trp-64; these experiments include pH profiles and H/D solvent isotope effects consistent with proton transfer, observation of approximately fourfold greater activation with the mutant containing Trp-64 compared with Gly-64, and the observation by x-ray crystallography of the binding of 4-MI associated with the indole side chain of Trp-64 in W5A-H64W HCA II. Proton donors bound at the less flexible side chain of Trp-64 in W5A-H64W HCA II do not show activation, but such donors bound at the more flexible Trp-64 of H64W HCA II do show activation, supporting suggestions that conformational mobility of the binding site is associated with more efficient proton transfer. Evaluation using Marcus theory showed that the activation of H64W HCA II by these proton donors was reflected in the work functions w(r) and w(p) rather than in the intrinsic Marcus barrier itself, consistent with the role of solvent reorganization in catalysis.


    Organizational Affiliation

    Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, Florida, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Carbonic anhydrase 2
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
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download SDF File 
Download CCD File 
A
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.204 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 42.092α = 90.00
b = 41.402β = 104.00
c = 71.928γ = 90.00
Software Package:
Software NamePurpose
CNSrefinement
DENZOdata reduction
CNSphasing
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-11-28
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance