Origin of life: a hypothesis for the origin of adaptor-mediated ordered synthesis of proteins and an explanation for the choice of terminating codons in the genetic code.
Life can be defined as a system of self-sustained chemical processes springing from the ordered synthesis of proteins directed by nucleic acids. To the notoriously difficult problem of the origin of this basic process of nucleic acid-directed protein synthesis, we give a solution of molecular interactions between pentanucleotides and amino acids. A particular conformation of a pentanucleotide forms a double sided template, with its 'inside' capable of nestling an amino acid while the 'outside' acts as an adaptor to a 'codon' triplet on long-chain nucleic acids. This serves as a primitive decoding system. An important aspect of our postulate is that a dynamic interaction is triggered, by this decoding system, through which amino acids are brought to juxtaposition facilitating peptide bond formation. Almost all the important and unique features of contemporary protein-synthesizing machinery are seen to be a direct and natural consequence of our postulate. The emergence of the termination codons also fits in, as a natural consequence of this molecular mechanism.
D000818:Animals; D003062:Codon / Q000235:genetics*; D005815:Genetic Code; D008957:Models, Genetic; D008961:Models, Structural; D009690:Nucleic Acid Conformation; D000069497:Origin of Life; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D012343:RNA, Transfer / Q000235:genetics; D013698:Templates, Genetic
D003062:Codon; D011506:Proteins; D012333:RNA, Messenger; D012343:RNA, Transfer