3TVN

Human Carbonic Anhydrase II Proton Transfer Mutant


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.175 
  • R-Value Observed: 0.177 

wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

Water Networks in Fast Proton Transfer during Catalysis by Human Carbonic Anhydrase II.

Mikulski, R.West, D.Sippel, K.H.Avvaru, B.S.Aggarwal, M.Tu, C.McKenna, R.Silverman, D.N.

(2013) Biochemistry 52: 125-131

  • DOI: https://doi.org/10.1021/bi301099k
  • Primary Citation of Related Structures:  
    3TVN, 3TVO, 4IDR

  • PubMed Abstract: 

    Variants of human carbonic anhydrase II (HCA II) with amino acid replacements at residues in contact with water molecules in the active-site cavity have provided insights into the proton transfer rates in this protein environment. X-ray crystallography and (18)O exchange measured by membrane inlet mass spectrometry have been used to investigate structural and catalytic properties of variants of HCA II containing replacements of Tyr7 with Phe (Y7F) and Asn67 with Gln (N67Q). The rate constants for transfer of a proton from His64 to the zinc-bound hydroxide during catalysis were 4 and 9 μs(-1) for Y7F and Y7F/N67Q, respectively, compared with a value of 0.8 μs(-1) for wild-type HCA II. These higher values observed for Y7F and Y7F/N67Q HCA II could not be explained by differences in the values of the pK(a) of the proton donor (His64) and acceptor (zinc-bound hydroxide) or by the orientation of the side chain of the proton shuttle residue His64. They appeared to be associated with a reduced level of branching in the networks of hydrogen-bonded water molecules between proton shuttle residue His64 and the zinc-bound solvent molecule as observed in crystal structures at 1.5-1.6 Å resolution. Moreover, Y7F/N67Q HCA II is unique among the variants studied in having a direct, hydrogen-bonded chain of water molecules between the zinc-bound solvent and N(ε) of His64. This study provides the clearest example to date of the relevance of ordered water structure to rate constants for proton transfer in catalysis by carbonic anhydrase.


  • Organizational Affiliation

    Department of Pharmacology, University of Florida, Gainesville, FL 32610, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Carbonic anhydrase 2A [auth X]258Homo sapiensMutation(s): 1 
Gene Names: CA2
EC: 4.2.1.1
UniProt & NIH Common Fund Data Resources
Find proteins for P00918 (Homo sapiens)
Explore P00918 
Go to UniProtKB:  P00918
PHAROS:  P00918
GTEx:  ENSG00000104267 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00918
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download Ideal Coordinates CCD File 
B [auth X]ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.175 
  • R-Value Observed: 0.177 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 42.005α = 90
b = 41.223β = 104.32
c = 72.059γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PHENIXrefinement
PDB_EXTRACTdata extraction
CrystalCleardata collection
HKL-2000data reduction
HKL-2000data scaling
PHENIXphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-08-08
    Type: Initial release
  • Version 1.1: 2012-12-26
    Changes: Database references
  • Version 1.2: 2013-01-23
    Changes: Database references
  • Version 1.3: 2017-11-08
    Changes: Refinement description
  • Version 1.4: 2024-02-28
    Changes: Data collection, Database references, Derived calculations