Antunes, Víctor U; Llontop, Edgar E; Vasconcelos, Fernanda N da Costa; Lopez de los Santos, Yossef; Oliveira, Ronaldo J; Lincopan, Nilton; Farah, Chuck S.; Doucet, Nicolas 
ORCID: https://orcid.org/0000-0002-1952-9380; Mittermaier, Anthony et Favaro, Denize C
(2019).
Importance of the β5-β6 Loop for the Structure, Catalytic Efficiency, and Stability of Carbapenem-Hydrolyzing Class D β-Lactamase Subfamily OXA-143
Biochemistry
, vol. 58
, nº 34.
pp. 3604-3616.
DOI: 10.1021/acs.biochem.9b00365.
Résumé
The class D β-lactamase OXA-143 has been described as an efficient penicillinase, oxacillinase, and carbapenemase. The D224A variant, known as OXA-231, was described in 2012 as exhibiting less activity toward imipenem and increased oxacillinase activity. Additionally, the P227S mutation was reported as a case of convergent evolution for homologous enzymes. To investigate the impact of both mutations (D224A and P227S), we describe in this paper a deep investigation of the enzymatic activities of these three homologues. OXA-143(P227S) presented enhanced catalytic activity against ampicillin, oxacillins, aztreonam, and carbapenems. In addition, OXA-143(P227S) was the only member capable of hydrolyzing ceftazidime. These enhanced activities were due to a combination of a higher affinity (lower Km) and a higher turnover number (higher kcat). We also determined the crystal structure of apo OXA-231. As expected, the structure of this variant is very similar to the published OXA-143 structure, except for the two M223 conformations and the absence of electron density for three solvent-exposed loop segments. Molecular dynamics calculations showed that both mutants experience higher flexibility compared to that of the wild-type form. Therefore, our results illustrate that D224A and P227S act as deleterious and positive mutations, respectively, within the evolutionary path of the OXA-143 subfamily toward a more efficient carbapenemase.
| Type de document: | Article |
|---|---|
| Mots-clés libres: | Peptides and proteins, Genetics, Monomers, Crystal structure, Assays |
| Centre: | Centre INRS-Institut Armand Frappier |
| Date de dépôt: | 22 juill. 2021 21:37 |
| Dernière modification: | 15 févr. 2022 15:32 |
| URI: | https://espace.inrs.ca/id/eprint/11533 |
Gestion Actions (Identification requise)
 |
Modifier la notice |