Thermosynthesis as energy source for the RNA World: A model for the bioenergetics of the origin of life

The thermosynthesis concept, biological free energy gain from thermal cycling, is combined with the concept of the RNA World. The resulting overall origin of life model suggests new explanations for the emergence of the genetic code and the ribosome. It is proposed that the first protein named pF1 obtained the energy to support the RNA World by a thermal variation of F1 ATP synthaseʹs binding change mechanism. It is further proposed that this pF1 was the single translation product during the emergence of the genetic machinery. During thermal cycling pF1 condensed many substrates with broad specificity, yielding NTPs and randomly constituted protein and RNA libraries that contained self-replicating RNA. The smallness of pF1 permitted the emergence of the genetic machinery by selection of RNA that increased the fraction of pF1s in the protein library: (1) an amino acids concatenating progenitor of rRNA bound to (2) a chain of ‘positional tRNAs’ linked by mutual recognition, and yielded a pF1 (or its main motif); this positional tRNA set gradually evolved to a set of regular tRNAs functioning according to the genetic code, with concomitant emergence of (3) an mRNA coding for pF1.