Structural Insights into the TLA-3 Extended-Spectrum β-Lactamase and Its Inhibition by Avibactam and OP0595
| Autor: | Akihiro Morinaka, Yoshiaki Sakamaki, Kouji Kimura, Mototsugu Yamada, Wanchun Jin, Jun-ichi Wachino, Minoru Yonezawa, Yoshichika Arakawa, Hiromasa Kurosaki, Yoshihiro Yamaguchi, Anupriya Kumar |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Cefotaxime Lactams medicine.drug_class Stereochemistry Avibactam 030106 microbiology Cephalosporin Microbial Sensitivity Tests medicine.disease_cause Crystallography X-Ray beta-Lactamases Acylation 03 medical and health sciences chemistry.chemical_compound Mechanisms of Resistance Catalytic Domain Hydrolase medicine Escherichia coli Humans Pharmacology (medical) Enzyme kinetics Pharmacology biology biology.organism_classification Enterobacteriaceae Cephalosporins 030104 developmental biology Infectious Diseases chemistry beta-Lactamase Inhibitors Azabicyclo Compounds medicine.drug |
| Zdroj: | Antimicrobial agents and chemotherapy. 61(10) |
| ISSN: | 1098-6596 |
| Popis: | The development of effective inhibitors that block extended-spectrum β-lactamases (ESBLs) and restore the action of β-lactams represents an effective strategy against ESBL-producing Enterobacteriaceae . We evaluated the inhibitory effects of the diazabicyclooctanes avibactam and OP0595 against TLA-3, an ESBL that we identified previously. Avibactam and OP0595 inhibited TLA-3 with apparent inhibitor constants ( K i app ) of 1.71 ± 0.10 and 1.49 ± 0.05 μM, respectively, and could restore susceptibility to cephalosporins in the TLA-3-producing Escherichia coli strain. The value of the second-order acylation rate constant ( k 2 / K , where k 2 is the acylation rate constant and K is the equilibrium constant) of avibactam [(3.25 ± 0.03) × 10 3 M −1 · s −1 ] was closer to that of class C and D β-lactamases ( k 2 / K , 4 M −1 · s −1 ) than that of class A β-lactamases ( k 2 / K , >10 4 M −1 · s −1 ). In addition, we determined the structure of TLA-3 and that of TLA-3 complexed with avibactam or OP0595 at resolutions of 1.6, 1.6, and 2.0 Å, respectively. TLA-3 contains an inverted Ω loop and an extended loop between the β5 and β6 strands (insertion after Ser237), which appear only in PER-type class A β-lactamases. These structures might favor the accommodation of cephalosporins harboring bulky R1 side chains. TLA-3 presented a high catalytic efficiency ( k cat / K m ) against cephalosporins, including cephalothin, cefuroxime, and cefotaxime. Avibactam and OP0595 bound covalently to TLA-3 via the Ser70 residue and made contacts with residues Ser130, Thr235, and Ser237, which are conserved in ESBLs. Additionally, the sulfate group of the inhibitors formed polar contacts with amino acid residues in a positively charged pocket of TLA-3. Our findings provide a structural template for designing improved diazabicyclooctane-based inhibitors that are effective against ESBL-producing Enterobacteriaceae . |
| Databáze: | OpenAIRE |
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