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The genetic code: a different perspective Instead of presenting codons in the order of first base, second base, third base (1-2-3), codons are presented in the order of 2-1-(2)-3.
RNA (A/ G/ C/ U): gold (second nucleotide), red (first nucleotide), green (third nucleotide).
Amino acids (in one-letter abbreviation) appear to cluster in structural/ functional groups.
Legend: (*) special feature, (u) unpolar, (p) polar, (OH) hydroxyl group, (r) conjugated pi electrons, (+) positive charge/ basic, (-) negative charge/ acidic.
For the first time, it is possible to group all the leucine, serine, arginine and stop codons together, revealing an ordered pattern behind what seemed random previously. The genetic code appears to have evolved through cooperative interplay between nucleic and amino acids. Deviations from the standard genetic code illustrate how the game plan to the game of life evolved over time in different organisms/ environments.
One possible explanation for the importance of the second codon base may lie in the interaction between mRNA and tRNA. If the tRNA docking process is not as smooth as a zipper but more like a swinging pendulum, it becomes conceivable that the initial interaction between mRNA and tRNA occurs at first at the central codon base, followed by the binding of the first codon base to the anticodon, then a swing back to the second codon base, then a swing to the third codon base and dissociation. The observed "wobble" at the third codon base may be due to the shortness of time available for the interactions to occur between codon- and anti-codon base because of interference with the dissociation process between the two RNA species, and checking for size (purine/ pyrimidine bases) appears the more important criterion.
With greatest respect,
Website: www.rna-game.org |
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