A GTP-synthesizing ribozyme selected by metabolic coupling to an RNA polymerase ribozyme.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34613767.
- Also identified by DOI 10.1126/sciadv.abj7487 and PMC identifier 8494290.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Synthesis of RNA in early life forms required chemically activated nucleotides, perhaps in the same form of nucleoside 5′-triphosphates (NTPs) as in the contemporary biosphere. We show the development of a catalytic RNA (ribozyme) that generates the nucleoside triphosphate guanosine 5′-triphosphate (GTP) from the nucleoside guanosine and the prebiotically plausible cyclic trimetaphosphate. Ribozymes were selected from 1.6 × 10<sup>14</sup> different randomized sequences by metabolically coupling 6-thio GTP synthesis to primer extension by an RNA polymerase ribozyme within 10<sup>16</sup> emulsion droplets. Several functional RNAs were identified, one of which was characterized in more detail. Under optimized reaction conditions, this ribozyme produced GTP at a rate 18,000-fold higher than the uncatalyzed rate, with a turnover of 1.7-fold, and supported the incorporation of GTP into RNA oligomers in tandem with an RNA polymerase ribozyme. These results are discussed in the context of early life forms.