RESUMO
1-Deoxy-d-xylulose 5-phosphate (DXP) synthase catalyzes the thiamin diphosphate (ThDP)-dependent formation of DXP from pyruvate and d-glyceraldehyde 3-phosphate. DXP is at a metabolic branch point in bacteria, feeding into the methylerythritol phosphate pathway to indispensable isoprenoids and acting as a precursor for biosynthesis of essential cofactors in central metabolism, pyridoxal phosphate and ThDP, the latter of which is also required for DXP synthase catalysis. DXP synthase follows a unique random sequential mechanism and possesses an unusually large active site. These features have guided the design of sterically demanding alkylacetylphosphonates (alkylAPs) toward the development of selective DXP synthase inhibitors. alkylAPs studied here display selective, low µM inhibitory activity against DXP synthase. They are weak inhibitors of bacterial growth in standard nutrient rich conditions. However, bacteria are significantly sensitized to most alkylAPs in defined minimal growth medium, with minimal inhibitory concentrations (MICs) ranging from low µM to low mM and influenced by alkyl-chain length. The longest analog (C8) displays the weakest antimicrobial activity and is a substrate for efflux via AcrAB-TolC. The dependence of inhibitor potency on growth environment emphasizes the need for antimicrobial screening conditions that are relevant to the in vivo microbial microenvironment during infection. DXP synthase expression and thiamin supplementation studies offer support for DXP synthase as an intracellular target for some alkylAPs and reveal both the challenges and intriguing aspects of these approaches to study target engagement.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Escherichia coli/efeitos dos fármacos , Organofosfonatos/farmacologia , Transferases/antagonistas & inibidores , Aldose-Cetose Isomerases/genética , Aldose-Cetose Isomerases/metabolismo , Antibacterianos/síntese química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Domínio Catalítico , Clonagem Molecular , Inibidores Enzimáticos/síntese química , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Gliceraldeído 3-Fosfato/metabolismo , Testes de Sensibilidade Microbiana , Organofosfonatos/síntese química , Plasmídeos/química , Plasmídeos/metabolismo , Fosfato de Piridoxal/metabolismo , Ácido Pirúvico/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Tiamina Pirofosfato/metabolismo , Transferases/genética , Transferases/metabolismoRESUMO
Antiseptic agents are the primary arsenal to disinfect skin and prevent pathogens spreading within the host as well as into the surroundings; however the Food and Drug Administration published a report in 2015 requiring additional validation of nearly all current antiseptic agents before their continued use can be allowed. This vulnerable position calls for urgent identification of novel antiseptic agents. Recently, the ability of a deep eutectic, Choline And Geranate (CAGE), to treat biofilms of Pseudomonas aeruginosa and Salmonella enterica was demonstrated. Here it is reported that CAGE exhibits broad-spectrum antimicrobial activity against a number of drug-resistant bacteria, fungi, and viruses including clinical isolates of Mycobacterium tuberculosis, Staphylococcus aureus, and Candida albicans as well as laboratory strains of Herpes Simplex Virus. Studies in human keratinocytes and mice show that CAGE affords negligible local or systemic toxicity, and an ≈180-14 000-fold improved efficacy/toxicity ratio over currently used antiseptic agents. Further, CAGE penetrates deep into the dermis and treats pathogens located in deep skin layers as confirmed by the ability of CAGE in vivo to treat Propionibacterium acnes infection. In combination, the results clearly demonstrate CAGE holds promise as a transformative platform antiseptic agent for preventive as well as therapeutic applications.