Origin of Life and the Phosphate Transfer Catalyst

Abstract

In this paper, we revisit several issues relevant to origin-of-life research and propose a Phosphate Transfer Catalyst hypothesis that furthers our understanding of some of the key events in prebiotic chemical evolution. In the Phosphate Transfer Catalyst hypothesis, we assume the existence of hypothetical metallopeptides with phosphate transfer activity that use abundant polyphosphates as both substrates and energy sources. Nonspecific catalysis by this phosphate transfer catalyst would provide a variety of different products such as phosphoryl amino acids, nucleosides, polyphosphate nucleotides, nucleic acids, and aminoacylated nucleic acids. Moreover, being an autocatalytic set and metabolic driver at the same time, it could possibly replicate itself and produce a collective system of two polymerases; a nucleic acid able to catalyze peptide bond formation and a peptide able to polymerize nucleic acids. The genetic code starts at first as a system that reduces the energy barrier by bringing substrates (2'/3' aminoacyl-nucleotides) together, an ancestral form of the catalysis performed by modern ribosomes. Key Words: Origin of life-Prebiotic chemistry-Catalysis-Nucleic acids. Astrobiology 17, 277-285.

Phosphates as Energy Sources to Expand Metabolic Networks

“…What is more, phosphorus was thought to play a crucial role both in the prebiotic synthesis of important precursors of RNA and proteins [5,6,7] and in primordial energy metabolism [8,9,10]. These viewpoints support the importance of phosphorus in the origin of life.…”

“…Moreover, the ‘phosphorus problem’ itself might have been solved by recent findings. Phosphite, a kind of water-soluble, reactive reduced-state phosphorus, was recently proposed to be an available prebiotic phosphorus source [10]. It has been proven that phosphite can be produced from the extraterrestrial phosphide mineral-schreibersite and is present in early Archean marine carbonates at significant levels [11,12].…”

Small Cyclic Peptide for Pyrophosphate Dependent Ligation in Prebiotic Environments

“…We embarked on this study as an approach to a search for a Phosphate Transfer Catalyst [ 4 ], which in our opinion is crucial in prebiotic emergence of bioenergetics and of information-storing polymers. We chose a top-bottom approach reducing the active sites to merely few amino acids put on a relatively stable scaffold of cyclic heksapeptide.…”

“…A common feature of the biochemistry of all known organisms is their dependence on phosphorylated molecules as the main intermediates in bioenergetic processes [ 3 ]. As such the question of phosphorylation, availability of phosphorus, and formation of organophosphorus compounds and more specifically organophosphates has been approached multiple times by researchers interested in prebiotic chemistry and the origin-of-life process [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. We have previously postulated [ 4 ] the existence of a hypothetical molecule named Phosphate Transfer Catalyst, which would be of crucial importance in the prebiotic emergence of biochemical pathways.…”

“…We decided to rationally design a number of short peptides which would exhibit low energy coordination to Mg 2+ and to pyrophosphate. We hoped that such an approach will allow to create a Phosphate Transfer Catalysts [ 4 ] exhibiting properties allowing for further complexification of the prebiotic soup into a complex interacting mixture described as ‘prebiotic ecology’ [ 29 ].…”