Abstract |
Combinations of group A and B streptogramins (i.e., dalfopristin and quinupristin) are "last-resort" antibiotics for the treatment of infections caused by Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium. Resistance to streptogramins has arisen via multiple mechanisms, including the deactivation of the group A component by the large family of virginiamycin O- acetyltransferase (Vat) enzymes. Despite the structural elucidation performed for the VatD acetyltransferase, which provided a general molecular framework for activity, a detailed characterization of the essential catalytic and antibiotic substrate-binding determinants in Vat enzymes is still lacking. We have determined the crystal structure of S. aureus VatA in apo, virginiamycin M1- and acetyl-coenzyme A ( CoA)-bound forms and provide an extensive mutagenesis and functional analysis of the structural determinants required for catalysis and streptogramin A recognition. Based on an updated genomic survey across the Vat enzyme family, we identified key conserved residues critical for VatA activity that are not part of the O-acetylation catalytic apparatus. Exploiting such constraints of the Vat active site may lead to the development of streptogramin A compounds that evade inactivation by Vat enzymes while retaining binding to their ribosomal target.
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Authors | Peter J Stogios, Misty L Kuhn, Elena Evdokimova, Patrice Courvalin, Wayne F Anderson, Alexei Savchenko |
Journal | Antimicrobial agents and chemotherapy
(Antimicrob Agents Chemother)
Vol. 58
Issue 12
Pg. 7083-92
(Dec 2014)
ISSN: 1098-6596 [Electronic] United States |
PMID | 25223995
(Publication Type: Journal Article, Research Support, N.I.H., Extramural)
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Copyright | Copyright © 2014, American Society for Microbiology. All Rights Reserved. |
Chemical References |
- Anti-Bacterial Agents
- Bacterial Proteins
- Recombinant Proteins
- Acetyl Coenzyme A
- Streptogramin A
- Acetyltransferases
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Topics |
- Acetyl Coenzyme A
(chemistry)
- Acetyltransferases
(antagonists & inhibitors, chemistry, genetics)
- Amino Acid Sequence
- Anti-Bacterial Agents
(chemistry)
- Bacterial Proteins
(antagonists & inhibitors, chemistry, genetics)
- Catalytic Domain
- Crystallography, X-Ray
- Drug Resistance, Bacterial
(genetics)
- Gene Expression
- Gram-Negative Bacteria
(chemistry, enzymology)
- Gram-Positive Bacteria
(chemistry, enzymology)
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Protein Binding
- Recombinant Proteins
(chemistry, genetics)
- Sequence Alignment
- Streptogramin A
(chemistry)
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