1HCB

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


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Observed: 0.177 

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
  • Primary Citation of Related Structures:  
    1HCB

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

    Organizational Affiliation

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



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CARBONIC ANHYDRASE IA260Homo sapiensMutation(s): 0 
Gene Names: CA1
EC: 4.2.1.1
Find proteins for P00915 (Homo sapiens)
Explore P00915 
Go to UniProtKB:  P00915
NIH Common Fund Data Resources
PHAROS  P00915
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download CCD File 
A
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
BCT
Query on BCT

Download CCD File 
A
BICARBONATE ION
C H O3
BVKZGUZCCUSVTD-UHFFFAOYSA-M
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Observed: 0.177 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 81.85α = 90
b = 75.31β = 90
c = 37.76γ = 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