title: Chloramphenicol-erythromycin resistance mutations in a 23S rRNA gene of Escherichia coli.
abstract: Two chloramphenicol resistance mutations were isolated in an Escherichia coli rRNA operon (rrnH) located on a multicopy plasmid. Both mutations also confer resistance to 14-atom lactone ring macrolide antibiotics, but they do not confer resistance to 16-atom lactone ring macrolide antibiotics or other inhibitors of the large ribosomal subunit. Classic genetic and recombinant DNA methods were used to map the two mutations to 154-base-pair regions of the 23S RNA genes. DNA sequencing of these regions revealed that chloramphenicol-erythromycin resistance results from a guanine-to-adenine transition at position 2057 of the 23S RNA genes of both independently isolated mutants. These mutations affect a region of 23S RNA strongly implicated in peptidyl transfer and known to interact with a variety of peptidyl transferase inhibitors.
mesh_terms: D001483:Base Sequence; D002701:Chloramphenicol / Q000494:pharmacology*; D002872:Chromosome Deletion; D002874:Chromosome Mapping; D004352:Drug Resistance, Microbial; D004917:Erythromycin / Q000494:pharmacology*; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D009154:Mutation; D009690:Nucleic Acid Conformation; D010458:Peptidyl Transferases / Q000037:antagonists & inhibitors; D012335:RNA, Ribosomal / Q000235:genetics*; D013329:Structure-Activity Relationship
chemical_list: D012335:RNA, Ribosomal; D004917:Erythromycin; D002701:Chloramphenicol; D010458:Peptidyl Transferases