1URT

MURINE CARBONIC ANHYDRASE V


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.8 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.137 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure-based design of an intramolecular proton transfer site in murine carbonic anhydrase V.

Heck, R.W.Boriack-Sjodin, P.A.Qian, M.Tu, C.Christianson, D.W.Laipis, P.J.Silverman, D.N.

(1996) Biochemistry 35: 11605-11611

  • DOI: 10.1021/bi9608018

  • PubMed Abstract: 
  • Carbonic anhydrase V (CA V) is a mitochondrial enzyme that catalyzes the hydration of CO2 to produce bicarbonate and a proton. The catalytic properties of wild-type murine CA V suggest the presence of a proton shuttle residue having pKa = 9.2, the ro ...

    Carbonic anhydrase V (CA V) is a mitochondrial enzyme that catalyzes the hydration of CO2 to produce bicarbonate and a proton. The catalytic properties of wild-type murine CA V suggest the presence of a proton shuttle residue having pKa = 9.2, the role of which is to transfer a proton from zinc-bound water to solution in the hydration direction to regenerate the zinc hydroxide form of the enzyme. Two likely candidates for shuttle residues are the tyrosines at positions 64 and 131 in the active site cavity. The crystal structure of wild-type carbonic anhydrase V [Boriack-Sjodin et al. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 10949-10953] shows that the side chain of Tyr 64 is forced into an orientation pointing away from the zinc by Phe 65, although Tyr 131 is oriented toward the zinc. We have prepared mutants of murine CA V replacing both Tyr 64 and Tyr 131 with His and Ala and investigated the proton shuttle mechanism using stopped-flow spectrophotometry and the depletion of 18O from CO2 measured by mass spectrometry. Experiments with both single and double mutations showed that neither position 64 nor position 131 was a prominent site for proton transfer. However, a double mutant of CA V containing the two replacements, Tyr 64-->His and Phe 65-->Ala, demonstrated enhanced proton transfer with an apparent pKa of 6.8 and maximal contribution to kcat of 2.2 x 10(5) s-1. In addition to the altered catalytic properties, the crystal structure of the His 64/Ala 65 double mutant strongly suggested proton transfer by His 64 after removal of the steric hindrance of Phe 65. This is the first structure-based design of an efficient proton transfer site in an enzyme.


    Related Citations: 
    • Structure Determination of Murine Mitochondrial Carbonic Anhydrase V at 2.45-A Resolution: Implications for Catalytic Proton Transfer and Inhibitor Design
      Boriack-Sjodin, P.A.,Heck, R.W.,Laipis, P.J.,Silverman, D.N.,Christianson, D.W.
      (1995) Proc.Natl.Acad.Sci.USA 92: 10949
    • Catalytic Properties of Mouse Carbonic Anhydrase V
      Heck, R.W.,Tanhauser, S.M.,Manda, R.,TU, C.,Laipis, P.J.,Silverman, D.N.
      (1994) J.Biol.Chem. 269: 24742


    Organizational Affiliation

    Department of Pharmacology, University of Florida, Gainesville 32610-0267, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CARBONIC ANHYDRASE V
A
248Mus musculusMutations: H43Y, A44F
Gene Names: Ca5a (Ca5, Car5, Car5a)
EC: 4.2.1.1
Find proteins for P23589 (Mus musculus)
Go to UniProtKB:  P23589
Small Molecules
Ligands 1 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
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.8 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.137 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 101.090α = 90.00
b = 67.520β = 107.60
c = 48.860γ = 90.00
Software Package:
Software NamePurpose
X-PLORrefinement
MOSFLMdata reduction
X-PLORphasing
X-PLORmodel building

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1997-01-11
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance