Formation of the genetic code

Formation of the genetic code was investigated by integration of data on amino acid composition of protein functional sites and on development of amino acid biosynthesis pathways, with the novel proposition that encodings were directed by proteins synthesized by dimers of tRNAs paired through anticodons. Elimination of anticodonic 5’A facilitated the encoding process. The succession of encodings begins with Glycine and Serine, indicating that early metabolism was centered on assimilation of one-carbon units. Early amino acids (GS,LDN,EPKFR) compose peptides predominantly stabilizing the aminotermini of proteins against degradation, and building RNA-binding motifs with mostly non-periodic conformations. Compartmentalization of amino acids in modules of tRNA dimers results in minimization of the consequences of errors along the coding/decoding processes. Termination anticodons were deleted due to their interference with the initiation mechanism. The system of tRNA dimers is integrated through development of associations between the synthetases.