Struck J C, Erdmann V A
Freie Universität Berlin, Institut für Biochemie, Federal Republic of Germany.
Eur J Biochem. 1990 Aug 28;192(1):17-24. doi: 10.1111/j.1432-1033.1990.tb19189.x.
Small cytoplasmic RNA (scRNA; 271 nucleotides) is an abundant, stable RNA identified in the Gram-positive eubacterium Bacillus subtilis. Several findings suggest an important role of scRNA in protein biosynthesis: it shares structural and biochemical features with the Escherichia coli 4.5S RNA (114 nucleotides), a molecule known to be involved in this process, and it can complement the essential function of 4.5S RNA in vivo. The common apical hairpin motif of scRNA and 4.5S RNA also exists in eukaryotic 7SL RNA, the RNA component of the signal recognition particle. To elucidate the higher-order structure of scRNA, we have combined a phylogenetic approach with a biochemical one. The sequence of scRNA from a thermophilic relative of B. subtilis, Bacillus stearothermophilus, was determined and compared with the B. subtilis scRNA. In addition, the solution structure of B. stearothermophilus scRNA was probed with single- and double-strand-specific nucleases. Both types of analysis support a secondary structure model for scRNA that strongly resembles 4.5S RNA and respective parts of 7SL RNA. The results provide further evidence for the suggestion of a functional relationship between these RNAs.
小细胞质RNA（scRNA；271个核苷酸）是在革兰氏阳性真细菌枯草芽孢杆菌中发现的一种丰富且稳定的RNA。多项研究结果表明scRNA在蛋白质生物合成中具有重要作用：它与大肠杆菌4.5S RNA（114个核苷酸）具有结构和生化特征，已知该分子参与此过程，并且它可以在体内补充4.5S RNA的基本功能。scRNA和4.5S RNA常见的顶端发夹基序也存在于真核生物7SL RNA（信号识别颗粒的RNA成分）中。为了阐明scRNA的高级结构，我们将系统发育方法与生化方法相结合。测定了枯草芽孢杆菌的嗜热亲缘种嗜热脂肪芽孢杆菌的scRNA序列，并与枯草芽孢杆菌的scRNA进行了比较。此外，用单链和双链特异性核酸酶探测了嗜热脂肪芽孢杆菌scRNA的溶液结构。这两种分析都支持scRNA的二级结构模型，该模型与4.5S RNA和7SL RNA的相应部分非常相似。这些结果为这些RNA之间功能关系的推测提供了进一步的证据。
