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Can the RNA World Still Function without Cytidine?
- Source :
-
Molecular biology and evolution [Mol Biol Evol] 2020 Jan 01; Vol. 37 (1), pp. 71-83. - Publication Year :
- 2020
-
Abstract
- Most scenarios for the origin of life assume that RNA played a key role in both catalysis and information storage. The A, U, G, and C nucleobases in modern RNA all participate in secondary structure formation and replication. However, the rapid deamination of C to U and the absence of C in meteorite samples suggest that prebiotic RNA may have been deficient in cytosine. Here, we assess the ability of RNA sequences formed from a three-letter AUG alphabet to perform both structural and genetic roles in comparison to sequences formed from the AUGC alphabet. Despite forming less thermodynamically stable helices, the AUG alphabet can find a broad range of structures and thus appears sufficient for catalysis in the RNA World. However, in the AUG case, longer sequences are required to form structures with an equivalent complexity. Replication in the AUG alphabet requires GU pairing. Sequence fidelity in the AUG alphabet is low whenever G's are present in the sequence. We find that AUG sequences evolve to AU sequences if GU pairing is rare, and to RU sequences if GU pairing is common (R denotes A or G). It is not possible to conserve a G at a specific site in either case. These problems do not rule out the possibility of an RNA World based on AUG, but they show that it wouldbe significantly more difficult than with a four-base alphabet.<br /> (© The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Subjects :
- Molecular Structure
Origin of Life
RNA physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1537-1719
- Volume :
- 37
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Molecular biology and evolution
- Publication Type :
- Academic Journal
- Accession number :
- 31504724
- Full Text :
- https://doi.org/10.1093/molbev/msz200