Crystal Structure of Carboxyltransferase from Staphylococcus aureus Bound to the Antibacterial Agent Moiramide B.
Silvers, M.A., Pakhomova, S., Neau, D.B., Silvers, W.C., Anzalone, N., Taylor, C.M., Waldrop, G.L.(2016) Biochemistry 55: 4666-4674
- PubMed: 27471863 
- DOI: https://doi.org/10.1021/acs.biochem.6b00641
- Primary Citation of Related Structures:  
5KDR - PubMed Abstract: 
The dramatic increase in the prevalence of antibiotic-resistant bacteria has necessitated a search for new antibacterial agents against novel targets. Moiramide B is a natural product, broad-spectrum antibiotic that inhibits the carboxyltransferase component of acetyl-CoA carboxylase, which catalyzes the first committed step in fatty acid synthesis. Herein, we report the 2.6 Å resolution crystal structure of moiramide B bound to carboxyltransferase. An unanticipated but significant finding was that moiramide B bound as the enol/enolate. Crystallographic studies demonstrate that the (4S)-methyl succinimide moiety interacts with the oxyanion holes of the enzyme, supporting the notion that an anionic enolate is the active form of the antibacterial agent. Structure-activity studies demonstrate that the unsaturated fatty acid tail of moiramide B is needed only for entry into the bacterial cell. These results will allow the design of new antibacterial agents against the bacterial form of carboxyltransferase.
Organizational Affiliation: 
Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853-1301, United States.