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Triplet-Encoded Prebiotic RNA Aminoacylation
Meng Su1, Christian Schmitt2, Ziwei Liu1
1MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
Journal of the American Chemical Society
|July 12, 2023
Summary
Before enzymes, RNA could be selectively aminoacylated without them. This study shows sequence-dependent, enzyme-free aminoacylation of RNA, suggesting a second genetic code in the RNA acceptor stem.
Area of Science:
- Origin of life studies
- Molecular biology
- Biochemistry
Background:
- Translation requires amino acids attached to tRNAs by aminoacyl-tRNA synthetases.
- The origin of this selective aminoacylation before enzyme evolution is unknown.
Purpose of the Study:
- To investigate enzyme-free, sequence-dependent aminoacylation of RNA.
- To explore potentially prebiotic routes for primordial tRNA aminoacylation.
Main Methods:
- Investigated two prebiotic routes for aminoacyl-tRNA acceptor stem-overhang mimics.
- Analyzed oligonucleotide efficiency in aminoacylation.
- Examined chemoselectivity and stereoselectivity of aminoacylation from mixed anhydride donors.
Main Results:
- Demonstrated enzyme-free, chemoselective aminoacylation of RNA.
- Overhang sequences had minimal impact on chemoselectivity.
- Aminoacylation selectivity depended on the terminal three base pairs of the RNA stem.
Conclusions:
- Supports the hypothesis of a second genetic code within the RNA acceptor stem.
- Provides insight into early RNA-based amino acid activation mechanisms.
- Suggests a plausible pathway for the origin of genetic coding.
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