title: Base-pairing between 23S rRNA and tRNA in the ribosomal A site.
abstract: The aminoacyl (A site) tRNA analog 4-thio-dT-p-C-p-puromycin (s4TCPm) photochemically cross-links with high efficiency and specificity to G2553 of 23S rRNA and is peptidyl transferase reactive in its cross-linked state, establishing proximity between the highly conserved 2555 loop in domain V of 23S rRNA and the universally conserved CCA end of tRNA. To test for base-pairing interactions between 23S rRNA and aminoacyl tRNA, site-directed mutations were made at the universally conserved nucleotides U2552 and G2553 of 23S rRNA in both E. coli and B. stearothermophilus ribosomal RNA and incorporated into ribosomes. Mutations at G2553 resulted in dominant growth defects in E. coli and in decreased levels of peptidyl transferase activity in vitro. Genetic analysis in vitro of U2552 and G2553 mutant ribosomes and CCA end mutant tRNA substrates identified a base-pairing interaction between C75 of aminoacyl tRNA and G2553 of 23S rRNA.
authors.affiliation: Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
authors.forename: D F
authors.initials: DF
authors.lastname: Kim
authors.forename: R
authors.initials: R
authors.lastname: Green
mesh_terms: D015075:2-Aminopurine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D020029:Base Pairing / Q000235:genetics*; D001665:Binding Sites; D017124:Conserved Sequence / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D005798:Genes, Bacterial / Q000235:genetics; D001411:Geobacillus stearothermophilus / Q000201:enzymology / Q000235:genetics; D006860:Hydrogen Bonding; D007700:Kinetics; D016297:Mutagenesis, Site-Directed / Q000235:genetics; D009154:Mutation / Q000235:genetics; D009690:Nucleic Acid Conformation; D010458:Peptidyl Transferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011691:Puromycin / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D012338:RNA, Ribosomal, 23S / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013489:Suppression, Genetic / Q000235:genetics
chemical_list: D012338:RNA, Ribosomal, 23S; D012346:RNA, Transfer, Amino Acyl; D015075:2-Aminopurine; C007300:2,6-diaminopurine; D011691:Puromycin; D010458:Peptidyl Transferases