Novel Bacterial Acetyl Coenzyme A Carboxylase Inhibitors with Antibiotic Efficacy In Vivo

Abstract

The pseudopeptide pyrrolidinedione antibiotics, such as moiramide B, have recently been discovered to target the multisubunit acetyl coenzyme A (acetyl-CoA) carboxylases of bacteria. In this paper, we describe synthetic variations of each moiety of the modularly composed pyrrolidinediones, providing insight into structure-activity relationships of biochemical target activity, in vitro potency, and in vivo efficacy. The novel derivatives showed highly improved activities against gram-positive bacteria compared to those of previously reported variants. The compounds exhibited a MIC 90 value of 0.1 g/ml against a broad spectrum of Staphylococcus aureus clinical isolates. No cross-resistance to antibiotics currently used in clinical practice was observed. Resistance mutations induced by pyrrolidinediones are exclusively located in the carboxyltransferase subunits of the bacterial acetyl-CoA carboxylase, indicating the identical mechanisms of action of all derivatives tested. Improvement of the physicochemical profile was achieved by salt formation, leading to aqueous solubilities of up to 5 g/liter. For the first time, the in vitro activity of this compound class was compared with its in vivo efficacy, demonstrating a path from compounds weakly active in vivo to agents with significant efficacy. In a murine model of S. aureus sepsis, the 100% effective dose of the best compound reported was 25 mg/kg of body weight, only fourfold higher than that of the comparator molecule linezolid. The obvious improvements achieved by chemical derivatization reflect the potential of this novel antibiotic compound class for future therapy.

Perturbation of Staphylococcus aureus Gene Expression by the Enoyl-Acyl Carrier Protein Reductase Inhibitor AFN-1252

“…However, the molecular basis for the differential susceptibility of Gram-positive pathogens to FASII inhibitors has been uncovered, providing an understanding of why FASII inhibitors are effective against S. aureus even in the presence of an extracellular source of fatty acids (7). These data resolved the debate concerning the validity of using fatty acid synthesis inhibitors to treat S. aureus infections (8,9) and are consistent with the examples of fatty acid synthesis inhibitors that show efficacy in S. aureus-infected animal models (5,8,(10)(11)(12)(13)(14).…”

Directed evolution can rapidly improve the activity of chimeric assembly-line enzymes

“…2c) because substitution of the valine in andrimid with other aliphatic amino acids does not disrupt its antibacterial activity (27), whereas replacement of its ␤-phenylalanine or its glycinederived succinimide abrogates activity (26). We constructed a knockout of the admK gene (admK::cat) in a cosmid expressing the andrimid gene cluster and confirmed that a plasmid-borne admK gene complements this knockout (SI Fig.…”

“…Because previous work had shown that substituting isoleucine for valine confers increased potency on a synthetic derivative of andrimid (27), we constructed a second AdmK chimera by replacing AdmK-A with the isoleucine-specific BacA-A1 domain from the Bacillus licheniformis bacitracin NRPS (29). Complementation of the admK::cat strain with plasmid-encoded AdmK-BacA-A1 generated the corresponding isoleucine-containing derivative of andrimid (6) with a 7-fold reduction in product yield compared with that of the wild-type enzyme (Fig.…”

“…AdmK-BacA-A1 had no discernible phenotypic impairment (Fig. 3c), likely because of increased antibacterial activity of 8 as compared with andrimid against the indicator strain (27). After a single round of mutagenesis and screening, we isolated a clone (5A-06) from 21 retested hits with a 4.5-fold improvement in product yield (Fig.…”

Cell-free Determination of Binary Complexes That Comprise Extended Protein-Protein Interaction Networks of Yersinia pestis

“…6B-6F), whereas several previously reported interactions were recapitulated in the Y. pestis PPi network (Fig. 6B, 6D, 6E) (35)(36)(37). Of the annotated proteins within the network (n ϭ 218), one-quarter could be mapped to a protein class (Fig.…”