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Sequential binding of cobalt(II) to metallo-beta-lactamase CcrA. Biochemistry 2006 Jan 31;45(4):1313-20

Date

01/25/2006

Pubmed ID

16430228

DOI

10.1021/bi051105n

Scopus ID

2-s2.0-31644444386 (requires institutional sign-in at Scopus site)   39 Citations

Abstract

In an effort to probe Co(II) binding to metallo-beta-lactamase CcrA, EPR, EXAFS, and (1)H 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). (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(1) site in the enzyme.

Author List

Periyannan GR, Costello AL, Tierney DL, Yang KW, Bennett B, Crowder MW

Author

Brian Bennett D.Phil. Professor and Chair in the Physics department at Marquette University




MESH terms used to index this publication - Major topics in bold

Bacterial Proteins
Binding Sites
Cobalt
Electron Spin Resonance Spectroscopy
Escherichia coli
Kinetics
Magnetic Resonance Spectroscopy
Metals
Models, Molecular
Protein Binding
Spectrophotometry, Ultraviolet
Spectroscopy, Fourier Transform Infrared
beta-Lactamases