title: Dependence of the 16S rRNA decoding region structure on Mg2+, subunit association, and temperature.
abstract: The effects of Mg2+ concentration, subunit association, and temperature on the structure of 16S rRNA in the Escherichia coli ribosome were investigated using UV cross-linking and gel electrophoresis analysis. Mg2+ concentrations between 1 and 20 mM and temperatures between 5 and 55 degreesC had little effect on the frequency of 12 of the 14 cross-links in 30S subunits and modest effects on the same cross-links in 70S ribosomes. In contrast, two cross-links, C967 x C1400 and C1402 x C1501, involving rRNA in the decoding region are present in 30S subunits only above 3 mM Mg2+, increase in frequency at higher Mg2+ concentration, and are both more frequent when 50S subunits are included in the reactions. In 70S ribosomes, the cross-link C1402 x C1501 increases but the cross-link C967 x C1400 decreases at higher Mg2+ concentrations. One cross-link, C1397 x U1495, is detected only in 70S ribosomes and decreases in frequency as Mg2+ concentration is increased. An additional cross-link, A1093 x C1182, decreases upon subunit association. The cross-link frequency differences indicate that the arrangement of the decoding region of the 16S rRNA, but not in the rest of the subunit, is readily altered by Mg2+ ions and subunit association.
authors.affiliation: Department of Biochemistry, North Carolina State University, Raleigh 27695-7622, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Noah
authors.forename: P
authors.initials: P
authors.lastname: Wollenzien
mesh_terms: D001483:Base Sequence; D004926:Escherichia coli; D005815:Genetic Code; D008274:Magnesium / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D012336:RNA, Ribosomal, 16S / Q000737:chemistry* / Q000378:metabolism; D012269:Ribosomal Proteins / Q000737:chemistry / Q000378:metabolism; D012270:Ribosomes / Q000737:chemistry / Q000378:metabolism; D013329:Structure-Activity Relationship; D013696:Temperature; D014466:Ultraviolet Rays
chemical_list: D012336:RNA, Ribosomal, 16S; D012269:Ribosomal Proteins; C040469:ribosomal protein S30; D008274:Magnesium