Lorenz S, Hartmann R K, Schultze S, Ulbrich N, Erdmann V A
Freic Universität Berlin, Institut für Biochemie, FRG.
Biochimie. 1989 Nov-Dec;71(11-12):1185-91. doi: 10.1016/0300-9084(89)90022-9.
The availabilities of single-stranded 5S rRNA regions c, d and d' for base pairing interactions were analyzed by using synthetic DNA oligomers. Hybrid formation was detected by the endonucleolytical mode of the RNA-DNA specific action of RNase H. Provided that the hybrid interaction involved 6 successive base pairs, 5S rRNA loop c nucleotides 42-47 displayed accessibility in Escherichia coli, Bacillus stearothermophilus and Thermus thermophilus 5S rRNAs as well as in eukaryotic 5S rRNAs from Saccharomyces carlsbergensis, Rattus rattus and Equisetum arvense. Investigating eubacterial 5S rRNA regions d and d' (nucleotides 71-76 and 99-105, respectively), susceptibility was observed in E. coli 5S rRNA which, however, decreases in B. stearothermophilus and even more so in T. thermophilus 5S rRNA. For additional evaluation of the data obtained by RNase H cleavage, association constants of the hexanucleotides were determined by equilibrium dialysis at 4 degrees C for B. stearothermophilus 5S rRNA. The results obtained reveal that nucleotides 36-41 of B. stearothermophilus 5S rRNA are inaccessible for Watson-Crick interaction, which suggests that this part of loop c is in a structurally constrained configuration, or buried in the tertiary structure or involved in tertiary interactions.
利用合成的DNA寡聚物分析了单链5S rRNA区域c、d和d'进行碱基配对相互作用的可能性。通过核糖核酸酶H的RNA-DNA特异性作用的内切核酸酶模式检测杂交体的形成。如果杂交相互作用涉及6个连续的碱基对，5S rRNA环c的核苷酸42 - 47在大肠杆菌、嗜热脂肪芽孢杆菌和嗜热栖热菌的5S rRNA以及来自卡尔斯伯酵母、褐家鼠和平平马先蒿的真核5S rRNA中都表现出可及性。研究真细菌5S rRNA区域d和d'（分别为核苷酸71 - 76和99 - 105），在大肠杆菌5S rRNA中观察到敏感性，然而在嗜热脂肪芽孢杆菌中敏感性降低，在嗜热栖热菌5S rRNA中甚至更低。为了进一步评估通过核糖核酸酶H切割获得的数据，在4℃下通过平衡透析法测定嗜热脂肪芽孢杆菌5S rRNA六核苷酸的缔合常数。所得结果表明，嗜热脂肪芽孢杆菌5S rRNA的核苷酸36 - 41无法进行沃森-克里克相互作用，这表明环c的这部分处于结构受限的构型，或者埋藏在三级结构中，或者参与三级相互作用。
