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Sequential Binding of Cobalt(II) to Metallo-β-lactamase CcrA
  • Gopal R. Periyannan, Miami University - Oxford
  • Alison L. Costello, University of New Mexico
  • David L. Tierney, University of New Mexico
  • Ke-Wu Yang, Miami University - Oxford
  • Brian Bennett, Marquette University
  • Michael W. Crowder, Miami University - Oxford
Document Type
Format of Original
8 p.
Publication Date
American Chemical Society
Original Item ID
doi: 10.1021/bi051105n

In an effort to probe Co(II) binding to metallo-β-lactamase CcrA, EPR, EXAFS, and 1H NMR studies were conducted on CcrA containing 1 equiv (1-Co(II)-CcrA) and 2 equiv (Co(II)Co(II)-CcrA) of Co(II). The EPR spectra of 1-Co(II)-CcrA and Co(II)Co(II)-CcrA are distinct and indicate 5/6-coordinate Co(II) ions. The EPR spectra also reveal the absence of significant spin-exchange coupling between the Co(II) ions in Co(II)Co(II)-CcrA. EXAFS spectra of 1-Co(II)-CcrA suggest 5/6-coordinate Co(II) with two or more histidine ligands. EXAFS spectra of Co(II)Co(II)-CcrA also indicate 5/6 ligands at a similar average distance to 1-Co(II)-CcrA, including an average of about two histidines per Co(II). 1H NMR spectra for 1-Co(II)-CcrA revealed seven paramagnetically shifted resonances, three of which were solvent-exchangeable, while the NMR spectra for Co(II)Co(II)-CcrA showed at least 16 shifted resonances, including an additional solvent-exchangeable resonance and a resonance at 208 ppm. The data indicate sequential binding of Co(II) to CcrA and that the first Co(II) binds to the consensus Zn1 site in the enzyme.


Biochemistry, Vol. 45, No. 4 (January 2006): 1313-1320. DOI.

Brian Bennett was affiliated with Medical College of Wisconsin at the time of publication.

Citation Information
Gopal R. Periyannan, Alison L. Costello, David L. Tierney, Ke-Wu Yang, et al.. "Sequential Binding of Cobalt(II) to Metallo-β-lactamase CcrA" Biochemistry (2006) ISSN: 0006-2960
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