title: The importance of base pairing in the penultimate stem of Escherichia coli 16S rRNA for ribosomal subunit association.
abstract: The influence of base pairing in the penultimate stem of Escherichia coli 16S rRNA (defined as nt 1409-1491) on ribosome function has been addressed by the construction of mutations in this region of rRNA. Two sets of mutations were made on either side of a structurally conserved region in the penultimate stem that disrupted base pairing, while a third set of mutations replaced the wild-type sequence with other base pair combinations. The effects of these mutations were analyzed in vivo and in vitro . The mutations that disrupted base pairing caused significant increases in cell doubling times as well as a severe subunit association defect and a modest increase in frame shifting and stop codon read-through. Restoration of base pairing restored wild-type growth rates, decoding and subunit association, indicating that base pairing in this region is essential for proper ribosome function.
authors.affiliation: Department of Molecular and Cell Biology and Biochemistry, Box G, Brown University, Providence, RI 02912, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Firpo
authors.forename: A E
authors.initials: AE
authors.lastname: Dahlberg
mesh_terms: D001483:Base Sequence; D004926:Escherichia coli; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000235:genetics / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*
chemical_list: D012329:RNA, Bacterial; D012330:RNA, Double-Stranded; D012336:RNA, Ribosomal, 16S