PMID:11369864
| Citation |
Beadle, BM, Nicholas, RA and Shoichet, BK (2001) Interaction energies between beta-lactam antibiotics and E. coli penicillin-binding protein 5 by reversible thermal denaturation. Protein Sci. 10:1254-9 |
|---|---|
| Abstract |
Penicillin-binding proteins (PBPs) catalyze the final stages of bacterial cell wall biosynthesis. PBPs form stable covalent complexes with beta-lactam antibiotics, leading to PBP inactivation and ultimately cell death. To understand more clearly how PBPs recognize beta-lactam antibiotics, it is important to know their energies of interaction. Because beta-lactam antibiotics bind covalently to PBPs, these energies are difficult to measure through binding equilibria. However, the noncovalent interaction energies between beta-lactam antibiotics and a PBP can be determined through reversible denaturation of enzyme-antibiotic complexes. Escherichia coli PBP 5, a D-alanine carboxypeptidase, was reversibly denatured by temperature in an apparently two-state manner with a temperature of melting (T(m)) of 48.5 degrees C and a van't Hoff enthalpy of unfolding (H(VH)) of 193 kcal/mole. The binding of the beta-lactam antibiotics cefoxitin, cloxacillin, moxalactam, and imipenem all stabilized the enzyme significantly, with T(m) values as high as +4.6 degrees C (a noncovalent interaction energy of +2.7 kcal/mole). Interestingly, the noncovalent interaction energies of these ligands did not correlate with their second-order acylation rate constants (k(2)/K'). These rate constants indicate the potency of a covalent inhibitor, but they appear to have little to do with interactions within covalent complexes, which is the state of the enzyme often used for structure-based inhibitor design. |
| Links |
PubMed PMC2374021 Online version:10.1110/ps.52001 |
| Keywords |
Acylation; Anti-Bacterial Agents/metabolism; Bacterial Proteins; Carrier Proteins/metabolism; Cefoxitin/metabolism; Circular Dichroism; Cloxacillin/metabolism; Escherichia coli/metabolism; Hexosyltransferases; Imipenem/metabolism; Models, Chemical; Moxalactam/metabolism; Muramoylpentapeptide Carboxypeptidase/metabolism; Penicillin-Binding Proteins; Peptidyl Transferases; Protein Binding; Protein Denaturation; Spectrometry, Fluorescence; Temperature; Thermodynamics; beta-Lactams/metabolism |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.