title: Influence of linker length and composition on enzymatic activity and ribosomal binding of neomycin dimers.
abstract: The human and bacterial A site rRNA binding as well as the aminoglycoside-modifying enzyme (AME) activity against a series of neomycin B (NEO) dimers is presented. The data indicate that by simple modifications of linker length and composition, substantial differences in rRNA selectivity and AME activity can be obtained. We tested five different AMEs with dimeric NEO dimers that were tethered via triazole, urea, and thiourea linkages. We show that triazole-linked dimers were the worst substrates for most AMEs, with those containing the longer linkers showing the largest decrease in activity. Thiourea-linked dimers that showed a decrease in activity by AMEs also showed increased bacterial A site binding, with one compound (compound 14) even showing substantially reduced human A site binding. The urea-linked dimers showed a substantial decrease in activity by AMEs when a conformationally restrictive phenyl linker was introduced. The information learned herein advances our understanding of the importance of the linker length and composition for the generation of dimeric aminoglycoside antibiotics capable of avoiding the action of AMEs and selective binding to the bacterial rRNA over binding to the human rRNA.
authors.affiliation: Nubad LLC, Greenville, South Carolina, USA.
authors.forename: Derrick
authors.initials: D
authors.lastname: Watkins
authors.affiliation: Department of Chemistry, Clemson University, Clemson, South Carolina, USA.
authors.forename: Sunil
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Department of Pharmaceutical Sciences, University of Kentucky, BioPharm Complex, Lexington, Kentucky, USA.
authors.forename: Keith D
authors.initials: KD
authors.lastname: Green
authors.affiliation: Nubad LLC, Greenville, South Carolina, USA Department of Chemistry, Clemson University, Clemson, South Carolina, USA dparya@clemson.edu sylviegtsodikova@uky.edu.
authors.forename: Dev P
authors.initials: DP
authors.lastname: Arya
authors.affiliation: Department of Pharmaceutical Sciences, University of Kentucky, BioPharm Complex, Lexington, Kentucky, USA dparya@clemson.edu sylviegtsodikova@uky.edu.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Garneau-Tsodikova
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D001665:Binding Sites / Q000187:drug effects; D001667:Binding, Competitive / Q000187:drug effects; D019281:Dimerization; D006801:Humans; D008826:Microbial Sensitivity Tests; D009355:Neomycin / Q000494:pharmacology*; D011487:Protein Conformation; D012335:RNA, Ribosomal / Q000096:biosynthesis; D012270:Ribosomes / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013890:Thiourea / Q000737:chemistry; D014230:Triazoles / Q000737:chemistry; D014508:Urea / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D012335:RNA, Ribosomal; D014230:Triazoles; D014508:Urea; D013890:Thiourea; D009355:Neomycin