Why Is AUG the Start Codon?: Theoretical Minimal RNA Rings: Maximizing Coded Information Biases 1st Codon for the Universal Initiation Codon AUG. (29th March 2020)

• Record Type: Journal Article
• Authors: Demongeot, Jacques; Seligmann, Hervé
• Is Part Of: BioEssays. Volume 42:Number 6(2020:Jun.)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-03-29
• Subjects: origins of life -- ribosomal RNA -- simulation -- teleonomy -- translation; Molecular biology -- Periodicals; Cytology -- Periodicals; Developmental biology -- Periodicals; 572.8
• DOI: 10.1002/bies.201900201
• Languages: English
• ISSNs: 0265-9247

Abstract

Abstract: The rational design of theoretical minimal RNA rings predetermines AUG as the universal start codon. This design maximizes coded amino acid diversity over minimal sequence length, defining in silico theoretical minimal RNA rings, candidate ancestral genes. RNA rings code for 21 amino acids and a stop codon after three consecutive translation rounds, and form a degradation‐delaying stem‐loop hairpin. Twenty‐five RNA rings match these constraints, ten start with the universal initiation codon AUG. No first codon bias exists among remaining RNA rings. RNA ring design predetermines AUG as initiation codon. This is the only explanation yet for AUG as start codon. RNA ring design determines additional RNA ring gene‐ and tRNA‐like properties described previously, because it presumably mimics constraints on life's primordial RNAs. Abstract : Twenty‐five 22‐nucleotide long RNAs forming either a ring or a stem‐loop hairpin fit the minmax problem of maximal coding diversity over the shortest length, potential primordial genes. Codon AUG is immediately 3'‐adjacent of the stop codon extremity in 40% of RNA rings, predetermining AUG as the natural universal initiation codon. Hence, these design constraints define theoretical RNAs matching modern genes.