{"doi":"10.17615/rnc7-y766","title":"Interaction energies between β-lactam antibiotics and E. coli penicillin-binding protein 5 by reversible thermal denaturation","abstract":"Penicillin-binding proteins (PBPs) catalyze the final stages of bacterial cell wall biosynthesis. PBPs form stable covalent complexes with β-lactam antibiotics, leading to PBP inactivation and ultimately cell death. To understand more clearly how PBPs recognize β-lactam antibiotics, it is important to know their energies of interaction. Because β-lactam antibiotics bind covalently to PBPs, these energies are difficult to measure through binding equilibria. However, the noncovalent interaction energies between β-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 (Tm) of 48.5°C and a van't Hoff enthalpy of unfolding (ΔHVH) of 193 kcal/mole. The binding of the β-lactam antibiotics cefoxitin, cloxacillin, moxalactam, and imipenem all stabilized the enzyme significantly, with ΔTm values as high as +4.6°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 (k2/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.","journal":"UNC Libraries","year":2020,"id":143797,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9536,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":106698,"name":"Brian K. Shoichet","orcid":"0000-0002-6098-7367","position":1,"is_corresponding":false},{"id":339442,"name":"Robert A. Nicholas","orcid":"0000-0003-2507-8974","position":2,"is_corresponding":false},{"id":299193,"name":"Beth M. Beadle","orcid":"0000-0001-5497-2831","position":0,"is_corresponding":true}],"reference_count":0,"raw_metadata":null,"created_at":"2026-07-18T23:17:41.821196Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}