Carbonic Anhydrase  
  Carbonic anhydrase II (CA) can be used as the transducer in a biosensor that measures zinc using either exogenous fluorescent sulfonamides or covalently attached fluorophores. CA-based sensors with a wide range of zinc affinities (6 orders of magnitude), kinetics, and specificities have been developed.  The use of CA to measure free metal ion concentrations in vivo has necessitated further improvements to this sensor. These include ratiometric sensors that can either be expressed in the cells or introduced into the cell by a cell importation tag.

Active site of Carbonic anhydrase


The ratiometric sensors use sulfonamides that bind to the holo-enzyme by either a covalently attached fluorophore or the DsRed protein fused to the C-terminus and the FRET donor and acceptor respectively. We are also continuing to alter the metal specificity by mutating the second shell metal ligands, and enhancing the protein stability by introducing a disulfide bond to further optimize CA-based biosensors for the measurement of zinc and copper ions in both in vitro and in vivo conditions.  

Recent Publications     

  1. Zeng HH, Thompson RB, Maliwal BP, Fones GR, Moffett JW, Fierke CA.  Real-time determination of picomolar free Cu(II) in seawater using a fluorescence-based fiber optic biosensor. Anal Chem (2003) 75, 6807-12.
  2. Thompson RB, Peterson D, Mahoney W, Cramer M, Maliwal BP, Suh SW, Frederickson C, Fierke C, Herman P.  Fluorescent zinc indicators for neurobiology. J Neurosci Method (2002) 118, 63-75.
  3. Fierke CA, Thompson RB.  Fluorescence-based biosensing of zinc using carbonic anhydrase. Biometals (2001) 14, 205-22.

PubMed Search

Collaborators
Richard Thompson, University of Maryland

Project Researchers
Research Assistant
Andrea Stoddard

Graduate Student
Nissa Westerberg
Tamiika K Hurst

Questions about this project? Email Nissa at nwesterb@umich.edu

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