Sequential Binding of Cobalt(II) to Metallo-beta-lactamase CcrA
In an effort to probe Co(II) binding to metallo-{beta}-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). {sup 1}H 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 Zn{sub 1} site in the enzyme.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 914097
- Report Number(s):
- BNL-78665-2007-JA; BICHAW; TRN: US0801542
- Journal Information:
- Biochemistry, Vol. 45; ISSN 0006-2960
- Country of Publication:
- United States
- Language:
- English
Similar Records
A Noncanonical Metal Center Drives the Activity of the Sediminispirochaeta smaragdinae Metallo-β-lactamase SPS-1
Site Selective Binding of Zn(ll) ot Metallo-b-Lactamase L1 from Stenotrophomonas Maltophilia