Novel Aminoglycoside 2″-Phosphotransferase Identified in a Gram-Negative Pathogen
| Autor: | Sergei B. Vakulenko, Marta Toth, Nuno T. Antunes, Hilary Frase |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Dibekacin
Molecular Sequence Data Microbial Sensitivity Tests Biology Substrate Specificity Microbiology Campylobacter jejuni Structure-Activity Relationship Bacterial Proteins Mechanisms of Resistance Escherichia coli medicine Pharmacology (medical) Arbekacin Amino Acid Sequence Cloning Molecular Neamine Enzyme Assays Pharmacology Sequence Homology Amino Acid Aminoglycoside Molecular biology Recombinant Proteins Anti-Bacterial Agents Kinetics Phosphotransferases (Alcohol Group Acceptor) Aminoglycosides Infectious Diseases Amikacin Sisomicin Netilmicin Isepamicin medicine.drug |
| Zdroj: | Antimicrobial Agents and Chemotherapy. 57:452-457 |
| ISSN: | 1098-6596 0066-4804 |
| DOI: | 10.1128/aac.02049-12 |
| Popis: | Aminoglycoside 2″-phosphotransferases are the major aminoglycoside-modifying enzymes in clinical isolates of enterococci and staphylococci. We describe a novel aminoglycoside 2″-phosphotransferase from the Gram-negative pathogen Campylobacter jejuni , which shares 78% amino acid sequence identity with the APH(2″)-Ia domain of the bifunctional aminoglycoside-modifying enzyme aminoglycoside (6′) acetyltransferase-Ie/aminoglycoside 2″-phosphotransferase-Ia or AAC(6′)-Ie/APH(2″)-Ia from Gram-positive cocci, which we called APH(2″)-If. This enzyme confers resistance to the 4,6-disubstituted aminoglycosides kanamycin, tobramycin, dibekacin, gentamicin, and sisomicin, but not to arbekacin, amikacin, isepamicin, or netilmicin, but not to any of the 4,5-disubstituted antibiotics tested. Steady-state kinetic studies demonstrated that GTP, and not ATP, is the preferred cosubstrate for APH(2″)-If. The enzyme phosphorylates the majority of 4,6-disubstituted aminoglycosides with high catalytic efficiencies ( k cat / K m = 10 5 to 10 7 M −1 s −1 ), while the catalytic efficiencies against the 4,6-disubstituted antibiotics amikacin and isepamicin are 1 to 2 orders of magnitude lower, due mainly to the low apparent affinities of these substrates for the enzyme. Both 4,5-disubstituted antibiotics and the atypical aminoglycoside neamine are not substrates of APH(2″)-If, but are inhibitors. The antibiotic susceptibility and substrate profiles of APH(2″)-If are very similar to those of the APH(2″)-Ia phosphotransferase domain of the bifunctional AAC(6′)-Ie/APH(2″)-Ia enzyme. |
| Databáze: | OpenAIRE |
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