An RNA secondary structure switch between the inactive and active conformations of the Escherichia coli 30 S ribosomal subunit.
Psoralen cross-linking was used to produce intramolecular cross-links in the Escherichia coli 16 S ribosomal RNA in the inactive and active forms of the 30 S subunit. A number of psoralen cross-links were made in the inactive form that were not made in the active form. The most frequent of these cross-links was sequenced by a series of techniques and identified as C-924 to U-1532. In this region, a three-base complementary, (921-923).(1532-1534), forms a site where psoralen can stack and produce a cross-link between C-924 and U-1532. When psoralen monoadducts were placed on inactive subunits and the conformation was switched to the active form before cross-linking, a new cross-link involving U-1393 was detected. U-1393 is part of the complementarity, (923-925).(1391-1393), that has previously been proposed as being an element of the functional secondary structure on the basis of sequence comparison. The complementarity between (921-923).(1532-1534) occurs in most nonmitochondrial small subunit RNAs; however, there are several counter examples in which it does not occur. This suggests that this alternate secondary structure interaction is not necessary for the function of the 30 S subunit.
Ericson
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E.A. Doisy Department of Biochemistry, St. Louis University Medical Center, Missouri 63104.
Wollenzien
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P
D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012335:RNA, Ribosomal / Q000235:genetics*; D012336:RNA, Ribosomal, 16S / Q000235:genetics* / Q000648:ultrastructure; D012270:Ribosomes / Q000378:metabolism*
D012335:RNA, Ribosomal; D012336:RNA, Ribosomal, 16S