1HCB

ENZYME-SUBSTRATE INTERACTIONS: STRUCTURE OF HUMAN CARBONIC ANHYDRASE I COMPLEXED WITH BICARBONATE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Enzyme-substrate interactions. Structure of human carbonic anhydrase I complexed with bicarbonate.

Kumar, V.Kannan, K.K.

(1994) J.Mol.Biol. 241: 226-232

  • DOI: 10.1006/jmbi.1994.1491

  • PubMed Abstract: 
  • The structure of HCAI-HCO3- complex has been refined with 10-1.6A X-ray diffraction data to an R-value of 17.7%. The structure reveals monodentate binding of the HCO3- anion at an apical tetrahedral position to the zinc ion. The binding mode and inte ...

    The structure of HCAI-HCO3- complex has been refined with 10-1.6A X-ray diffraction data to an R-value of 17.7%. The structure reveals monodentate binding of the HCO3- anion at an apical tetrahedral position to the zinc ion. The binding mode and interactions of HCO3- in HCAI differ from that in HCAII. The activity linked H2O/OH- group in the free HCAI is replaced by the hydroxyl group of the bicarbonate anion. This result rules out the rearrangement of the bound HCO3- advocated earlier to explain the microscopic reversibility of the catalysed reaction. From the geometry of the H-bonds between Glu106-Thr199 pair and Glu117-His119 couple, the glutamic acids are expected to be ionized and accept H-bonds from their partners. The product-inhibiton by HCO3- anion is explained on the basis of proton localization on His119 in the Glu117-His119 couple. These results are consistent with the hypothesis that Glu117-His119 tunes the ionicity of the Zn2+ and the binding strength of HCO3- anion. A pi hydrogen bond is observed between a water and phenyl ring of the Tyr114 residue.


    Related Citations: 
    • Human Carbonic Anhydrase I-Iodide Complex: Structure and Inhibition Mechanism
      Kumar, V.,Satyamurthy, P.,Kannan, K.K.
      (1987) Acta Crystallogr.,Sect.A 43: C-23
    • Structure of Human Carbonic Anhydrase I Complexed with Gold Cyanide Inhibitor: Inhibition Mechanism
      Kumar, V.,Kannan, K.K.
      (1993) Acta Crystallogr.,Sect.A 49: 92


    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 Gene View: CA1
Go to UniProtKB:  P00915
Small Molecules
Ligands 2 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
BCT
Query on BCT

Download SDF File 
Download CCD File 
A
BICARBONATE ION
C H O3
BVKZGUZCCUSVTD-UHFFFAOYSA-M
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
BCTKi: 12000000 - 15000000 nM (100) BINDINGDB
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 81.850α = 90.00
b = 75.310β = 90.00
c = 37.760γ = 90.00
Software Package:
Software NamePurpose
PROLSQrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

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