Attwater James, Augustin Teresa L, Curran Joseph F, Kwok Samantha L Y, Ohlendorf Luis, Gianni Edoardo, Holliger Philipp
MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK.
UCL Department of Chemistry, London, UK.
Nat Chem. 2025 May 28. doi: 10.1038/s41557-025-01830-y.
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.
RNA复制被认为是生命起源中的关键过程。然而，酶促和非酶促RNA复制循环都受到“链分离问题”的阻碍，这是一种由RNA双链体的非凡稳定性及其快速重新退火动力学引起的产物抑制形式。在这里，我们表明RNA三磷酸三核苷酸可以通过结合并动力学捕获解离的单链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（+）链和（-）链都能进行指数复制，包括核酶本身的一个片段。对随机RNA序列库进行开放式复制产生了确定的复制RNA序列或不同序列库的逐渐出现。后者源于部分核酶自我复制以及新RNA序列的产生，其组成朝着假定的原始密码子漂移。这些结果为模拟原始RNA复制开辟了更广阔的机会。
