The Way forward for the Origin of Life: Prions and Prion-Like Molecules First Hypothesis

Abstract

In this paper the hypothesis that prions and prion-like molecules could have initiated the chemical evolutionary process which led to the eventual emergence of life is reappraised. The prions first hypothesis is a specific application of the protein-first hypothesis which asserts that protein-based chemical evolution preceded the evolution of genetic encoding processes. This genetics-first hypothesis asserts that an “RNA-world era” came before protein-based chemical evolution and rests on a singular premise that molecules such as RNA, acetyl-CoA, and NAD are relics of a long line of chemical evolutionary processes preceding the Last Universal Common Ancestor (LUCA). Nevertheless, we assert that prions and prion-like molecules may also be relics of chemical evolutionary processes preceding LUCA. To support this assertion is the observation that prions and prion-like molecules are involved in a plethora of activities in contemporary biology in both complex (eukaryotes) and primitive life forms. Furthermore, a literature survey reveals that small RNA virus genomes harbor information about prions (and amyloids). If, as has been presumed by proponents of the genetics-first hypotheses, small viruses were present during an RNA world era and were involved in some of the earliest evolutionary processes, this places prions and prion-like molecules potentially at the heart of the chemical evolutionary process whose eventual outcome was life. We deliberate on the case for prions and prion-like molecules as the frontier molecules at the dawn of evolution of living systems.

Screening for Primordial RNA–Peptide Interactions Using High-Density Peptide Arrays

“…The fact that both Met and Trp are encoded by only one codon could be explained by their late entry into SGC after combinatorial protocode fusion. Jheeta et al have summarized in detail the reasons for the late entry of Met and Trp into the genetic code [ 6 ].…”

“…The uniqueness of ribosomal translation [ 1 ] points to its complex evolutionary development [ 2 ] which is likely to have involved the co-evolution of ribonucleic acids and peptides [ 3 ]. The recently demonstrated peptide synthesis on complementary short oligonucleotide pairs [ 4 ] has become a strong argument in support of the “RNA/peptide world” concept [ 5 , 6 ].…”

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“…The first step, formation of secondary level structures in the form of αhelices and β-sheets is displayed in Figs. 11, where the red dotted lines are an indication of the presence of hydrogen bonds between two peptide strands [117]. The change from secondary to quaternary structure is illustrated in Fig.…”

“…One of the top issues with protein is associated with diseases due to misfolding of higher order protein structure, called prions [121], like Alzheimer symptom [122] or bovine spongiform encephalopathy (Mad cow disease) [123]. It is really interesting but still remains mysterious how the prions are generated, despite their importance of life science [117,124]. For these reasons, protein engineering tend to direct to therapeutics and pharmaceutics [119,125].…”

Review: Chemical Bonds in Molecular Aggregation – From Drinking Water to Nanocomposites

“…The first step, formation of secondary level structures in the form of αhelices and β-sheets is displayed in Figs. 11, where the red dotted lines are an indication of the presence of hydrogen bonds between two peptide strands [117]. The change from secondary to quaternary structure is illustrated in Fig.…”