title: Antimicrobial Activity, AME Resistance, and A-Site Binding Studies of Anthraquinone-Neomycin Conjugates.
abstract: The antibacterial effects of aminoglycosides are based on their association with the A-site of bacterial rRNA and interference with the translational process in the bacterial cell, causing cell death. The clinical use of aminoglycosides is complicated by resistance and side effects, some of which arise from their interactions with the human mitochondrial 12S rRNA and its deafness-associated mutations, C1494U and A1555G. We report a rapid assay that allows screening of aminoglycoside compounds to these classes of rRNAs. These screening tools are important to find antibiotics that selectively bind to the bacterial A-site rather than human, mitochondrial A-sites and its mutant homologues. Herein, we report our preliminary work on the optimization of this screen using 12 anthraquinone-neomycin (AMA-NEO) conjugates against molecular constructs representing five A-site homologues, Escherichia coli, human cytosolic, mitochondrial, C1494U, and A1555G, using a fluorescent displacement screening assay. These conjugates were also tested for inhibition of protein synthesis, antibacterial activity against 14 clinically relevant bacterial strains, and the effect on enzymes that inactivate aminoglycosides. The AMA-NEO conjugates demonstrated significantly improved resistance against aminoglycoside-modifying enzymes (AMEs), as compared with NEO. Several compounds exhibited significantly greater inhibition of prokaryotic protein synthesis as compared to NEO and were extremely poor inhibitors of eukaryotic translation. There was significant variation in antibacterial activity and MIC of selected compounds between bacterial strains, with Escherichia coli, Enteroccocus faecalis, Citrobacter freundii, Shigella flexneri, Serratia marcescens, Proteus mirabilis, Enterobacter cloacae, Staphylococcus epidermidis, and Listeria monocytogenes exhibiting moderate to high sensitivity (50-100% growth inhibition) whereas Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiellla pneumoniae, and MRSA strains expressed low sensitivity, as compared to the parent aminoglycoside NEO.
authors.affiliation: NUBAD, LLC , Greenville, South Carolina 29605, United States.
authors.forename: Natalya N
authors.initials: NN
authors.lastname: Degtyareva
authors.affiliation: Department of Chemistry, Clemson University , Clemson, South Carolina 29634, United States.
authors.forename: Changjun
authors.initials: C
authors.lastname: Gong
authors.affiliation: NUBAD, LLC , Greenville, South Carolina 29605, United States.
authors.forename: Sandra
authors.initials: S
authors.lastname: Story
authors.affiliation: School of Chemistry and Biochemistry, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States.
authors.forename: Nathanael S
authors.initials: NS
authors.lastname: Levinson
authors.affiliation: School of Chemistry and Biochemistry, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States.
authors.forename: Adegboyega K
authors.initials: AK
authors.lastname: Oyelere
authors.affiliation: College of Pharmacy, University of Kentucky , Lexington, Kentucky 40536-0596, United States.
authors.forename: Keith D
authors.initials: KD
authors.lastname: Green
authors.affiliation: College of Pharmacy, University of Kentucky , Lexington, Kentucky 40536-0596, United States.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Garneau-Tsodikova
authors.affiliation: NUBAD, LLC , Greenville, South Carolina 29605, United States.|Department of Chemistry, Clemson University , Clemson, South Carolina 29634, United States.
authors.forename: Dev P
authors.identifier: 0000-0001-5873-1066
authors.initials: DP
authors.lastname: Arya
mesh_terms: D000617:Aminoglycosides / Q000737:chemistry / Q000494:pharmacology*; D000880:Anthraquinones / Q000737:chemistry / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology*; D001665:Binding Sites; D004352:Drug Resistance, Microbial / Q000187:drug effects; D006801:Humans; D008826:Microbial Sensitivity Tests; D009154:Mutation; D009355:Neomycin / Q000737:chemistry / Q000494:pharmacology; D012329:RNA, Bacterial / Q000037:antagonists & inhibitors / Q000737:chemistry; D012335:RNA, Ribosomal / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics
chemical_list: D000617:Aminoglycosides; D000880:Anthraquinones; D000890:Anti-Infective Agents; D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D009355:Neomycin
keywords: aminoglycoside modifying enzymes; antibacterial activity; translation inhibition