Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Moto-oka 744, Fukuoka 819-0395, Japan.
J Mol Evol. 2013 Feb;76(1-2):48-58. doi: 10.1007/s00239-012-9536-x. Epub 2013 Jan 4.
In the early stages of the hypothetical RNA world, some primitive RNA catalysts (ribozymes) may have emerged through self-assembly of short RNA oligomers. Although they may be unstable against temperature fluctuations and other environmental changes, ligase ribozymes (ribozymes with RNA strand-joining activity) may resolve structural instability of self-assembling RNAs by converting them to the corresponding unimolecular formats. To investigate this possibility, we constructed a model system using a cross-ligation system composed of a pair of self-assembling ligase ribozymes. Their abilities to act as catalysts, substrates, and a cross-ligation system were analyzed with or without thermal pretreatment before the reactions. A pair of self-assembling ligase ribozymes, each of which can form multiple conformations, demonstrated that thermotolerance was acquired and accumulated through complex-formation that stabilized the active forms of the bimolecular ribozymes and also cross-ligation that produced the unimolecular ribozymes.
在假设的 RNA 世界的早期阶段，一些原始的 RNA 催化剂（核酶）可能通过短 RNA 寡聚物的自组装而出现。虽然它们可能对温度波动和其他环境变化不稳定，但连接酶核酶（具有 RNA 链连接活性的核酶）可以通过将它们转化为相应的单分子形式来解决自组装 RNA 的结构不稳定性。为了研究这种可能性，我们使用由一对自组装连接酶核酶组成的交联系统构建了一个模型系统。在反应之前，分析了它们在有或没有热预处理的情况下作为催化剂、底物和交联系统的能力。一对可以形成多种构象的自组装连接酶核酶表明，通过稳定双分子核酶的活性形式的复合物形成以及产生单分子核酶的交联，获得并积累了耐热性。
