| Autor: |
Kenchel, Josh, Vázquez-Salazar, Alberto, Wells, Reno, Brunton, Krishna, Janzen, Evan, Schultz, Kyle M., Liu, Ziwei, Li, Weiwei, Parker, Eric T., Dworkin, Jason P., Chen, Irene A. |
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| Zdroj: |
Nature Communications; 9/12/2024, Vol. 15 Issue 1, p1-9, 9p |
| Abstrakt: |
Modern life is essentially homochiral, containing D-sugars in nucleic acid backbones and L-amino acids in proteins. Since coded proteins are theorized to have developed from a prebiotic RNA World, the homochirality of L-amino acids observed in all known life presumably resulted from chiral transfer from a homochiral D-RNA World. This transfer would have been mediated by aminoacyl-RNAs defining the genetic code. Previous work on aminoacyl transfer using tRNA mimics has suggested that aminoacylation using D-RNA may be inherently biased toward reactivity with L-amino acids, implying a deterministic path from a D-RNA World to L-proteins. Using a model system of self-aminoacylating D-ribozymes and epimerizable activated amino acid analogs, we test the chiral selectivity of 15 ribozymes derived from an exhaustive search of sequence space. All of the ribozymes exhibit detectable selectivity, and a substantial fraction react preferentially to produce the D-enantiomer of the product. Furthermore, chiral preference is conserved within sequence families. These results are consistent with the transfer of chiral information from RNA to proteins but do not support an intrinsic bias of D-RNA for L-amino acids. Different aminoacylation structures result in different directions of chiral selectivity, such that L-proteins need not emerge from a D-RNA World. Life is homochiral, and prior work posited that D-RNA may interact preferentially with L-amino acids. Here, the authors show that self-aminoacylating D-RNAs do not have an intrinsic preference for L-amino acids, suggesting that either handedness could emerge from early living systems. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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