Biochemical and biophysical characterization of the OXA-48-like carbapenemase OXA-436.
Lund, B.A., Thomassen, A.M., Carlsen, T.J.W., Leiros, H.K.S.(2021) Acta Crystallogr F Struct Biol Commun 77: 312-318
- PubMed: 34473108 
- DOI: https://doi.org/10.1107/S2053230X21008645
- Primary Citation of Related Structures:  
7ODA - PubMed Abstract: 
The crystal structure of the class D β-lactamase OXA-436 was solved to a resolution of 1.80 Å. Higher catalytic rates were found at higher temperatures for the clinically important antibiotic imipenem, indicating better adaptation of OXA-436 to its mesophilic host than OXA-48, which is believed to originate from an environmental source. Furthermore, based on the most populated conformations during 100 ns molecular-dynamics simulations, it is postulated that the modulation of activity involves conformational shifts of the α3-α4 and β5-β6 loops. While these changes overall do not cause clinically significant shifts in the resistance profile, they show that antibiotic-resistance enzymes exist in a continuum. It is believed that these seemingly neutral differences in the sequence exist on a path leading to significant changes in substrate selectivity.
Organizational Affiliation: 
The Norwegian Structural Biology Centre (NorStruct), Department of Chemistry, UiT The Arctic University of Norway, 9037 Tromsø, Norway.