On the origin of sequence
Life , Volume 5 - Issue 4 p. 1629- 1637
Three aspects which make planet Earth special, and which must be taken in consideration with respect to the emergence of peptides, are the mineralogical composition, the Moon which is in the same size class, and the triple environment consisting of ocean, atmosphere, and continent. GlyGly is a remarkable peptide because it stimulates peptide bond formation in the Salt-Induced Peptide Formation reaction. The role glycine and aspartic acid play in the active site of RNA polymerase is remarkable too. GlyGly might have been the original product of coded peptide synthesis because of its importance in stimulating the production of oligopeptides with a high aspartic acid content, which protected small RNA molecules by binding Mg 2+ ions. The feedback loop, which is closed by having RNA molecules producing GlyGly, is proposed as the essential element fundamental to life. Having this system running, longer sequences could evolve, gradually solving the problem of error catastrophe. The basic structure of the standard genetic code (8 fourfold degenerate codon boxes and 8 split codon boxes) is an example of the way information concerning the emergence of life is frozen in the biological constitution of organisms: the structure of the code contains historical information.