Departments of Chemistry and Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Biochemistry. 2013 Feb 19;52(7):1227-35. doi: 10.1021/bi301646n. Epub 2013 Feb 5.
A special class of biochemical reactions involves a set of enzymes that generate additional copies of themselves and transfer heritable information from parent to progeny molecules, thus providing the basis for genetics and Darwinian evolution. Such a process has been realized with a pair of self-replicating RNA enzymes that undergo exponential amplification at a constant temperature. Exponential growth requires that the rate of production of new enzymes be directly proportional to the existing concentration of enzymes, which is the case for this system and provides a doubling time of ~20 min. However, the catalytic rate of the underlying enzymes is ~100-fold faster than the observed rate of replication. As in biological replication, other aspects of the system limit the generation time, chiefly the propensity of the substrate molecules to form nonproductive complexes that limit their availability for replication. An analysis of this and other kinetic properties of the self-replicating RNA enzymes reveals how exponential amplification is achieved and how the rate of amplification might be increased.
一类特殊的生化反应涉及一组酶，这些酶可以自我复制，并将遗传信息从亲代分子传递给子代分子，从而为遗传学和达尔文进化提供了基础。这种过程已经在一对自我复制的 RNA 酶中实现，它们在恒温下进行指数扩增。指数增长要求新酶的生成速率与酶的现有浓度成正比，这种情况适用于该系统，并提供了约 20 分钟的倍增时间。然而，基础酶的催化速率比观察到的复制速率快约 100 倍。与生物复制一样，系统的其他方面限制了生成时间，主要是底物分子形成非生产性复合物的倾向，这限制了它们用于复制的可用性。对自我复制 RNA 酶的这些和其他动力学特性的分析揭示了如何实现指数扩增，以及如何提高扩增速率。
