近日，英国MRC分子生物学实验室Philipp Holliger团队揭示了pH-冻融循环下的三核苷酸底物使聚合酶核酶能够进行开放式指数RNA复制。这一研究成果发表在2025年5月28日出版的《自然-化学》杂志上。

RNA复制被认为是生命起源的关键过程。然而，酶和非酶RNA复制周期都受到“链分离问题”的阻碍，这是一种由RNA双链的非凡稳定性及其快速再退火动力学引起的产物抑制形式。研究组发现RNA三核苷酸三磷酸盐可通过以单链形式结合并动力学捕获解离的RNA链来克服这个问题，同时作为RNA聚合酶核酶复制的底物。 

当与耦合的pH和冻融循环相结合时，这使得双链RNA的（+）和（-）链能够指数复制，包括核酶本身的片段。对随机RNA序列池进行开放式复制，要么产生明确的复制RNA序列，要么逐渐出现多样化的序列池。后者来源于部分核酶自我复制以及新RNA序列的产生，它们的组成向假设的原始密码子漂移。这些结果为模拟原始RNA复制提供了更广泛的机会。

附：英文原文

Title: Trinucleotide substrates under pH–freeze–thaw cycles enable open-ended exponential RNA replication by a polymerase ribozyme

Author: Attwater, James, Augustin, Teresa L., Curran, Joseph F., Kwok, Samantha L. Y., Ohlendorf, Luis, Gianni, Edoardo, Holliger, Philipp

Issue&Volume: 2025-05-28

Abstract: RNA replication is considered a key process in the origins of life. However, both enzymatic and non-enzymatic RNA replication cycles are impeded by the ‘strand separation problem’, a form of product inhibition arising from the extraordinary stability of RNA duplexes and their rapid reannealing kinetics. Here we show that RNA trinucleotide triphosphates can overcome this problem by binding to and kinetically trapping dissociated RNA strands in a single-stranded form, while simultaneously serving as substrates for replication by an RNA polymerase ribozyme. When combined with coupled pH and freeze–thaw cycles, this enabled exponential replication of both (+) and () strands of double-stranded RNAs, including a fragment of the ribozyme itself. Subjecting random RNA sequence pools to open-ended replication yielded either defined replicating RNA sequences or the gradual emergence of diverse sequence pools. The latter derived from partial ribozyme self-replication alongside generation of new RNA sequences, and their composition drifted towards hypothesized primordial codons. These results unlock broader opportunities to model primordial RNA replication.

DOI: 10.1038/s41557-025-01830-y

Source: https://www.nature.com/articles/s41557-025-01830-y