Takagi Yasuomi, Inoue Atsushi, Taira Kazunari
Contribution from the Gene Function Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Central 4, 1-1-1 Higashi, Tsukuba Science City 305-8562, Japan.
J Am Chem Soc. 2004 Oct 13;126(40):12856-64. doi: 10.1021/ja031991u.
The hammerhead ribozyme reaction is more complex than might have been expected, perhaps because of the flexibility of RNA, which would have enhanced the potential of RNA during evolution of and in the RNA world. Divalent Mg(2+) ions can increase the rate of the ribozyme-catalyzed reaction by approximately 10(9)-fold as compared to the background rate under standard conditions. However, the role of Mg(2+) ions is controversial since the reaction can proceed in the presence of high concentrations of monovalent ions, such as Li(+), Na(+), and NH(4)(+) ions, in the absence of divalent ions. We thus carried out ribozyme reactions under various conditions, and we obtained parameters that explain the experimental data. On the basis of the analysis, we propose a new pathway in the hammerhead ribozyme reaction in which divalent metal ions and monovalent ions act cooperatively.
锤头状核酶反应比预期的更为复杂，这可能是由于RNA的灵活性，在RNA世界的进化过程中及在该世界里，这种灵活性会增强RNA的潜力。与标准条件下的背景速率相比，二价镁离子（Mg²⁺）可使核酶催化反应的速率提高约10⁹倍。然而，镁离子的作用存在争议，因为在没有二价离子的情况下，反应可以在高浓度单价离子（如锂离子、钠离子和铵离子）存在时进行。因此，我们在各种条件下进行了核酶反应，并获得了解释实验数据的参数。基于该分析，我们提出了锤头状核酶反应的一条新途径，其中二价金属离子和单价离子协同起作用。
