On the origin of the genetic code: Signatures of its primordial complementarity in tRNAs and aminoacyl-tRNA synthetases

S. Rodin, A. S. Rodin

Research output: Contribution to journalArticle

57 Citations (Scopus)

Abstract

If the table of the genetic code is rearranged to put complementary codons face-to-face, it becomes apparent that the code displays latent mirror symmetry with respect to two sterically different modes of tRNA recognition. These modes involve distinct classes of aminoacyl-tRNA synthetases (aaRSs I and II) with recognition from the minor or major groove sides of the acceptor stem, respectively. We analyze the anticodon pairs complementary to the face-to-face codon couplets. Taking into account the invariant nucleotides on either side (5′ and 3′), we consider the risk of anticodon confusion and subsequent erroneous aminoacylation in the ancestral coding system. This logic leads to the conclusion that ribozymic precursors of tRNA synthetases had the same two complementary modes of tRNA aminoacylation. This surprising case of molecular mimicry (1) shows a key potential selective advantage arising from the partitioning of aaRSs into two classes, (2) is consistent with the hypothesis that the two aaRS classes were originally encoded by the complementary strands of the same primordial gene and (3) provides a 'missing link' between the classic genetic code, embodied in the anticodon, and the second, or RNA operational, code that is embodied mostly in the acceptor stem and is directly responsible for proper tRNA aminoacylation.

Original languageEnglish
Pages (from-to)341-355
Number of pages15
JournalHeredity
Volume100
Issue number4
DOIs
Publication statusPublished - Apr 2008

Fingerprint

aminoacyl tRNA ligases
aminoacylation
Genetic Code
Anticodon
Amino Acyl-tRNA Synthetases
genetic code
Transfer RNA
Transfer RNA Aminoacylation
codons
Codon
molecular mimicry
Molecular Mimicry
Aminoacylation
stems
ligases
Nucleotides
nucleotides
RNA
Genes
anticodons

Keywords

  • Complementary symmetry
  • Genetic code
  • RNA world
  • tRNA aminoacylation

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Genetics
  • Genetics(clinical)

Cite this

On the origin of the genetic code : Signatures of its primordial complementarity in tRNAs and aminoacyl-tRNA synthetases. / Rodin, S.; Rodin, A. S.

In: Heredity, Vol. 100, No. 4, 04.2008, p. 341-355.

Research output: Contribution to journalArticle

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