Ester‐Mediated Amide Bond Formation Driven by Wet–Dry Cycles: A Possible Path to Polypeptides on the Prebiotic Earth

Abstract

Although it is generally accepted that amino acids were present on the prebiotic Earth, the mechanism by which α-amino acids were condensed into polypeptides before the emergence of enzymes remains unsolved. Here, we demonstrate a prebiotically plausible mechanism for peptide (amide) bond formation that is enabled by α-hydroxy acids, which were likely present along with amino acids on the early Earth. Together, α-hydroxy acids and α-amino acids form depsipeptides—oligomers with a combination of ester and amide linkages—in model prebiotic reactions that are driven by wet–cool/dry–hot cycles. Through a combination of ester–amide bond exchange and ester bond hydrolysis, depsipeptides are enriched with amino acids over time. These results support a long-standing hypothesis that peptides might have arisen from ester-based precursors.

Evaporite Borate‐Containing Mineral Ensembles Make Phosphate Available and Regiospecifically Phosphorylate Ribonucleosides: Borate as a Multifaceted Problem Solver in Prebiotic Chemistry

“…[14] Furthermore,i fe xposed to aqueous runoff from basalts (as in the highlands of Mars,amodel for early Earth), [15] such environments,w ould collect alkaline borate (from serpentinization of basaltic olivine and the erosion of its igneous tourmalines [16] ). [14] Furthermore,i fe xposed to aqueous runoff from basalts (as in the highlands of Mars,amodel for early Earth), [15] such environments,w ould collect alkaline borate (from serpentinization of basaltic olivine and the erosion of its igneous tourmalines [16] ).…”

Folding, Assembly, and Persistence: The Essential Nature and Origins of Biopolymers

“…We (Hud) have proposed that the thermodynamic driver for synthesis and degradation on the ancient Earth would have been cycling water activity (Forsythe et al 2015), which was and is ubiquitous over the landmass of the Earth. Thus, it seems possible that polymers originated via simple (non-redox) chemistry that remained near equilibrium, rocking gently in the cradle of day/night cycling (Hud and Anet 2000).…”

Noncanonical RNA Nucleosides as Molecular Fossils of an Early Earth—Generation by Prebiotic Methylations and Carbamoylations

“…[12] Another methylated nucleoside,m 7 G, is part of the 5'-cap structure of eukaryotic mRNA. [14] Since RNAi sa ble to store genetic information and perform catalytic processes,t he hypothesis further posits that an early replicating cell could proliferate and maintain ap rimitive metabolism in the absence of coded proteins.N oncoded polypeptides [15,16] and simple anabolic pathways [17,18] may have supported an early RNA-based metabolism. [14] Since RNAi sa ble to store genetic information and perform catalytic processes,t he hypothesis further posits that an early replicating cell could proliferate and maintain ap rimitive metabolism in the absence of coded proteins.N oncoded polypeptides [15,16] and simple anabolic pathways [17,18] may have supported an early RNA-based metabolism.…”