Abiogenic evolution of aminoacyl-tRNA synthetase

Abstract

The origin of life on earth demands a prerequisite for abiogenic evolution of RNA which is believed to be highly destructive on the earth covered by boiling ocean. I have proposed a mechanism of evolution of RNA as a left-handed single-stranded helical lattice with a trend of condensation and dehydration of organic compounds under a condition of high pressure and high temperature in the mantle of the earth. All organic compounds and energy-rich polyphosphates were synthesized from a large amount of methane hydrate, inorganic phosphate and oxygen radicals that were produced from ferrous oxides by disintegration of uranium. The six-fold symmetrical structure of the lattice allowed to stack a lot of energy-rich compounds such as adenosine triphosphate and phosphor-lipids which were required for formation of cell membrane at the later stage. More importantly, the cavity formed inside the lattice allowed polymerization of small L-amino acids such as glycine, alanine, proline and serine that were required to protect RNAs from hydrolysis. The 6.5-fold symmetrical lattice allowed a little more larger L-amino acids to incorporate the protective proteins and formation of α–helices, but insertion of larger amino acids such as arginine and methionine were rather difficult. However, in the next stage of evolution of the lattice formation of left-handed single-stranded RNA, an 8 fold symmetrical lattice seems to incorporate arginines and the other larger amino acids, and also a dimeric relationship between the two neighbor strands suggests a possibility of aminoacyl-tRNA synthetase to evolve because some of the aminoacyl-tRNA synthetases were formed to be in dimeric form.