Emergence of native peptide sequences in prebiotic replication networks

Abstract

Biopolymer syntheses in living cells are perfected by an elaborate error correction machinery, which was not applicable during polymerization on early Earth. Scientists are consequently striving to identify mechanisms by which functional polymers were selected and further amplified from complex prebiotic mixtures. Here we show the instrumental role of non-enzymatic replication in the enrichment of certain product(s). To this end, we analyzed a complex web of reactions in β-sheet peptide networks, focusing on the formation of specific intermediate compounds and template-assisted replication. Remarkably, we find that the formation of several products in a mixture is not critically harmful, since efficient and selective template-assisted reactions serve as a backbone correction mechanism, namely, for keeping the concentration of the peptide containing the native backbone equal to, or even higher than, the concentrations of the other products. We suggest that these findings may shed light on molecular evolution processes that led to current biology.

A prebiotic template-directed peptide synthesis based on amyloids

“…In terms of chemical replication, previous studies have shown that a peptide amyloid can act as a template to accelerate the rate of condensation (via native chemical ligation) of two smaller peptides that comprise the amyloidogenic peptide 14 , 15 . Very recently, this concept was extended to include an interconverting network of 4 regio- and stereoisomers in which the parent amyloid acted as a template to enhance the yield of self-products at the expense of kinetically more favorable products 16 . Considering the structure of the β-sheet 17 , 18 it is clear that as a template, an amyloid should be stereoselective.…”

Amyloid and the origin of life: self-replicating catalytic amyloids as prebiotic informational and protometabolic entities

“…The prebiotic relevance of the β-sheet networks and assemblies was recently highlighted by Tena-Solsona et al [ 17 ] who provided evidence for emergent catalytic behavior of self-assembled low-molecular-weight peptide aggregates, and by Nanda et al [ 21 ] who demonstrated error correction within replication networks through the emergence of short polymers exhibiting selective autocatalytic properties. Very recently, Rout et al [ 26 ] showed that an amyloid can direct the sequence-, regio-, and stereo-selective condensation of amino acid synthesis, and that the templating reaction is stable over a wide range of pH (5.6–8.6) and temperature (25–90 °C).…”

Frankenstein or a Submarine Alkaline Vent: Who is Responsible for Abiogenesis?

“…In these same galleries the ammonia can go on to effect the amination of amino acids which may then polymerize to heterochiral peptides. Such peptides can act as nests to sequester functional anions and also to amalgamate to form amyloid . Note that on completion of the reductions green rust is normally oxidized to magnetite (Fe 3 O 4 ), hematite (Fe 2 O 3 ) and goethite (FeO[OH]) .…”

“…Green rust is dosed with Ni and Co, intercalated with [MoS 4 ] 2− and often coated with phosphate . These functional elements are also found in proteins, as co‐factors, and are responsible for much of the bioenergetic transformations of extant biology, including electron bifurcation As in the redox proteins, green rust—poised between reduced alkaline hydrothermal solution and nitrate‐bearing acidulous ocean water—would physico‐chemically oscillate between reduced and oxidized states …”