1HUH

DIFFERENCES IN ANIONIC INHIBITION OF HUMAN CARBONIC ANHYDRASE I REVEALED FROM THE STRUCTURES OF IODIDE AND GOLD CYANIDE INHIBITOR COMPLEXES


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Observed: 0.166 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Differences in anionic inhibition of human carbonic anhydrase I revealed from the structures of iodide and gold cyanide inhibitor complexes.

Kumar, V.Kannan, K.K.Sathyamurthi, P.

(1994) Acta Crystallogr D Biol Crystallogr 50: 731-738

  • DOI: 10.1107/S0907444994001873
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • The crystal structures of two anionic inhibitor complexes of human carbonic anhydrase I (HCAI), namely, HCAI-iodide and HCAI-Au(CN)(2)(-), have been refined by the restrained least-squares method at 2.2 and 2 A nominal resolution, respectively, with ...

    The crystal structures of two anionic inhibitor complexes of human carbonic anhydrase I (HCAI), namely, HCAI-iodide and HCAI-Au(CN)(2)(-), have been refined by the restrained least-squares method at 2.2 and 2 A nominal resolution, respectively, with good stereochemistry for the final models. The R values have improved from 30.3 to 16.6% for HCAI-iodide and from 28.8 to 17.1% for HCAI-Au(CN)(2)(-). The sites of inhibitor binding as elucidated are totally different in the two structures. The iodide anion replaces the zinc-bound H(2)O/OH(-) ligand and renders the enzyme inactive. This result confirms that the zinc-bound H(2)O/OH(-) is the activity-linked group in carbonic anhydrase enzymes. Au(CN)(2)(-) binds at a different and new site near the zinc ion, without liganding to the metal. The N atom of Au(CN)(2)(-) is within hydrogen-bonding distance of the zinc-bound H(2)O/OH(-) group which shifts by about 0.4 A away from the zinc ion in relation to its position in the native HCAI. It is proposed that the presence of the inhibitor Au(CN)(2)(-) results in a conformational reorientation of the activity-linked group, due to hydrogen-bond formation with the inhibitor, which in turn sterically hinders the binding of the substrate CO(2) molecule in the active site, leading to the inhibition of HCAI enzyme.


    Related Citations: 
    • Human Carbonic Anhydrase I-Iodide Complex: Structure and Function
      Kumar, V., Sathyamurthy, P., Kannan, K.K.
      (1987) Acta Crystallogr A 43: 21

    Organizational Affiliation

    Solid State Physics Division, Bhabha Atomic Research Centre, Bombay, India.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CARBONIC ANHYDRASE I
A
260Homo sapiensMutation(s): 0 
Gene Names: CA1
EC: 4.2.1.1
Find proteins for P00915 (Homo sapiens)
Go to UniProtKB:  P00915
NIH Common Fund Data Resources
PHAROS  P00915
Protein Feature View
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
IOD
Query on IOD

Download CCD File 
A
IODIDE ION
I
XMBWDFGMSWQBCA-UHFFFAOYSA-M
 Ligand Interaction
ZN
Query on ZN

Download CCD File 
A
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
IDOKi:  300000   nM  BindingDB
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Observed: 0.166 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 81.8α = 90
b = 75.2β = 90
c = 37.1γ = 90
Software Package:
Software NamePurpose
PROLSQrefinement

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1994-04-30
    Type: Initial release
  • Version 1.1: 2008-03-03
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-11-29
    Changes: Derived calculations, Other