Journal article

Structural basis for different substrate profiles of two closely related class D β-lactamases and their inhibition by halogens

  • Stojanoski, Vlatko Biochemistry Dpt, Baylor College of Medicine, Houston, United States - Pharmacology Dpt, Baylor College of Medicine, Houston, United States
  • Chow, Dar-Chone Pharmacology Dpt, Baylor College of Medicine, Houston, United States
  • Fryszczyn, Bartlomiej Biochemistry Dpt, Baylor College of Medicine, Houston, United States - Pharmacology Dpt, Baylor College of Medicine, Houston, United States
  • Hu, Liya Biochemistry Dpt, Baylor College of Medicine, Houston, United States
  • Nordmann, Patrice Molecular Microbiology Unit, Department of Medicine, University of Fribourg, Switzerland
  • Poirel, Laurent Molecular Microbiology Unit, Department of Medicine, University of Fribourg, Switzerland
  • Sankaran, Banumathi Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, United States
  • Prasad, B. V. Venkataram Biochemistry Dpt, Baylor College of Medicine, Houston, United States
  • Palzkill, Timothy Biochemistry Dpt, Baylor College of Medicine, Houston, United States - Pharmacology Dpt, Baylor College of Medicine, Houston, United States
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    02.06.2015
Published in:
  • Biochemistry. - 2015, vol. 54, no. 21, p. 3370–3380
English OXA-163 and OXA-48 are closely related class D β-lactamases that exhibit different substrate profiles. OXA-163 hydrolyzes oxyimino-cephalosporins, particularly ceftazidime, while OXA-48 prefers carbapenem substrates. OXA-163 differs from OXA-48 by one substitution (S212D) in the active-site β5 strand and a four-amino acid deletion (214-RIEP-217) in the loop connecting the β5 and β6 strands. Although the structure of OXA-48 has been determined, the structure of OXA-163 is unknown. To further understand the basis for their different substrate specificities, we performed enzyme kinetic analysis, inhibition assays, X-ray crystallography, and molecular modeling. The results confirm the carbapenemase nature of OXA-48 and the ability of OXA-163 to hydrolyze the oxyimino-cephalosporin ceftazidime. The crystal structure of OXA-163 determined at 1.72 Å resolution reveals an expanded active site compared to that of OXA-48, which allows the bulky substrate ceftazidime to be accommodated. The structural differences with OXA-48, which cannot hydrolyze ceftazidime, provide a rationale for the change in substrate specificity between the enzymes. OXA-163 also crystallized under another condition that included iodide. The crystal structure determined at 2.87 Å resolution revealed iodide in the active site accompanied by several significant conformational changes, including a distortion of the β5 strand, decarboxylation of Lys73, and distortion of the substrate-binding site. Further studies showed that both OXA-163 and OXA-48 are inhibited in the presence of iodide. In addition, OXA-10, which is not a member of the OXA-48-like family, is also inhibited by iodide. These findings provide a molecular basis for the hydrolysis of ceftazidime by OXA-163 and, more broadly, show how minor sequence changes can profoundly alter the active-site configuration and thereby affect the substrate profile of an enzyme.
Faculty
Faculté des sciences et de médecine
Department
Médecine 3ème année
Language
  • English
Classification
Biology
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/304169
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