Abstract
Since methionine is capable of self-activation, the dipeptides formed by the reaction of its activated form with another amino acid were over-represented in the primitive ocean. This hypothesis gives a key role to methionine in the development of life on the Earth. It could explain why a methionine residue begins the synthesis of all proteins, while it is usually not necessary for its catalytic activity, and why the start codon is relatively variable in prokaryotes.
Funding
We thank “Labex Arcane” (ANR-11-LABX-0003-01) for the funding of K. V. Raghavendra Rao's grant.