Morris D R, Dahlberg J E, Dahlberg A E
Nucleic Acids Res. 1974 Oct;1(10):1249-58. doi: 10.1093/nar/1.10.1249.
Electrophoresis of ribosomal RNA in polyacrylamide-agarose composite gels separates 16S and 23S species into multiple bands. These bands of RNA represent multiple conformational forms of the molecules as judged by oligonucleotide analysis of the 16S RNA. Gel electrophoresis was used to test for cation-specific conformational changes in ribosomal RNA. Relative to magnesium-equilibrated RNA, barium ion and putrescine induced alterations in the electrophoretic behavior of ribosomal RNA while calcium ion produced no change. Exchange of a critical level of bound magnesium ion for barium or putrescine was necessary for these changes to take place. The alterations in electrophoretic behavior were unaffected by simply restoring magnesium ion, but in addition required heating for reversal. We suggest that these conformational changes are a result of interaction at a specific class of cation binding sites previously observed with intact ribosomes.
核糖体RNA在聚丙烯酰胺-琼脂糖复合凝胶中的电泳可将16S和23S种类分离成多条带。通过对16S RNA的寡核苷酸分析判断，这些RNA条带代表了分子的多种构象形式。凝胶电泳用于检测核糖体RNA中阳离子特异性的构象变化。相对于镁平衡的RNA，钡离子和腐胺可诱导核糖体RNA电泳行为的改变，而钙离子则无变化。这些变化发生的必要条件是将关键水平的结合镁离子换成钡离子或腐胺。电泳行为的改变不受简单恢复镁离子的影响，而是还需要加热才能逆转。我们认为，这些构象变化是先前在完整核糖体中观察到的特定类阳离子结合位点相互作用的结果。
