Sequential Binding of Cobalt(II) to Metallo-β-lactamase CcrABiochemistry
Format of Original8 p.
PublisherAmerican Chemical Society
Original Item IDdoi: 10.1021/bi051105n
AbstractIn 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.
Citation InformationGopal 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
Available at: http://works.bepress.com/gopal_periyannan/2/