1F2W

THE MECHANISM OF CYANAMIDE HYDRATION CATALYZED BY CARBONIC ANHYDRASE II REVEALED BY CRYOGENIC X-RAY DIFFRACTION


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.218 
  • R-Value Work: 0.166 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Mechanism of cyanamide hydration catalyzed by carbonic anhydrase II suggested by cryogenic X-ray diffraction.

Guerri, A.Briganti, F.Scozzafava, A.Supuran, C.T.Mangani, S.

(2000) Biochemistry 39: 12391-12397


  • PubMed Abstract: 
  • The three-dimensional structure of a possible intermediate in the hydration reaction of cyanamide to urea catalyzed by human carbonic anhydrase II (hCAII) has been determined by cryocrystallographic techniques. The crystal structure shows that two di ...

    The three-dimensional structure of a possible intermediate in the hydration reaction of cyanamide to urea catalyzed by human carbonic anhydrase II (hCAII) has been determined by cryocrystallographic techniques. The crystal structure shows that two different adducts are formed under the experimental conditions and that they have different occupancy in the crystal. The high occupancy form consists of a binary hCAII-cyanamide complex where the substrate has replaced the zinc-bound hydroxide anion present in the native enzyme, maintaining the tetrahedral geometry around the metal ion. The second, low-occupancy form consists of a hCAII-cyanamide-water ternary complex where the catalytic zinc ion, still being bound to cyanamide, is approached by a water molecule in a five-coordinate adduct. While the first form can be considered a nonproductive complex, the second form may represent an intermediate state of the catalyzed reaction where the water molecule is about to perform a nucleophilic attack on the zinc-activated cyanamide substrate. The structural evidence is consistent with the kinetic data previously reported about this recently described hydrolytic reaction catalyzed by hCAII, and indicates that a different mechanism with respect to that generally accepted for the physiologic carbon dioxide hydration reaction may be adopted by the enzyme, depending on the substrate chemical properties.


    Organizational Affiliation

    Dipartimento di Chimica, Università di Siena, Via Aldo Moro, I-53100 Siena, Italy.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CARBONIC ANHYDRASE II
A
259Homo 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 4 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
CNN
Query on CNN

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Download CCD File 
A
CYANAMIDE
C H2 N2
XZMCDFZZKTWFGF-UHFFFAOYSA-N
 Ligand Interaction
HGB
Query on HGB

Download SDF File 
Download CCD File 
A
4-(HYDROXYMERCURY)BENZOIC ACID
C7 H6 Hg O3
WMHRYLDWLOGHSG-UHFFFAOYSA-M
 Ligand Interaction
HG
Query on HG

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Download CCD File 
A
MERCURY (II) ION
Hg
BQPIGGFYSBELGY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.218 
  • R-Value Work: 0.166 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 42.158α = 90.00
b = 41.742β = 104.42
c = 72.307γ = 90.00
Software Package:
Software NamePurpose
SAINTdata scaling
REFMACrefinement
SAINTdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-06-08
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-10-11
    Type: Advisory, Data collection