title: Base changes at position 792 of Escherichia coli 16S rRNA affect assembly of 70S ribosomes.
abstract: To investigate the function of base 792 of 16S rRNA in 30S ribosomes of Escherichia coli, the wild-type (adenine) residue was changed to guanine, cytosine, or uracil by oligonucleotide-directed mutagenesis. Each base change conferred a unique phenotype on the cells. Cells containing plasmid pKK3535 with G792 or T792 showed no difference in generation time in LB broth containing ampicillin, whereas cells with C792 exhibited a 20% increase in generation time in this medium. To study the effect on cell growth of a homogeneous population of mutant ribosomes, the mutations were cloned into the 16S rRNA gene on pKK3535 carrying a spectinomycin-resistance marker (thymine at position 1192), and the cells were grown with spectinomycin. Cells containing G792 or C792 showed 16% and 56% increases in generation time, respectively, and a concomitant decrease in 35S assimilation into proteins. Cells with T792 did not grow in spectinomycin-containing medium. Maxicell analyses indicated decreasing ability to form 70S ribosomes from 30S subunits containing guanine, cytosine, or uracil at position 792 in 16S rRNA. It appeared that C792-containing 30S ribosomes had lost the ability to bind initiation factor 3.
authors: Department of Biology, Haverford College, PA 19041.
authors: M
authors: M
authors: Santer
authors: E
authors: E
authors: Bennett-Guerrero
authors: S
authors: S
authors: Byahatti
authors: S
authors: S
authors: Czarnecki
authors: D
authors: D
authors: O'Connell
authors: M
authors: M
authors: Meyer
authors: J
authors: J
authors: Khoury
authors: X
authors: X
authors: Cheng
authors: I
authors: I
authors: Schwartz
authors: J
authors: J
authors: McLaughlin
mesh_terms: D001483:Base Sequence; D004352:Drug Resistance, Microbial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D010957:Plasmids; D012335:RNA, Ribosomal / Q000235:genetics*; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012270:Ribosomes / Q000378:metabolism*; D000198:Spectinomycin / Q000494:pharmacology
chemical_list: D012335:RNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D000198:Spectinomycin