Potassium Ions are More Effective than Sodium Ions in Salt Induced Peptide Formation

Abstract

Prebiotic peptide formation under aqueous conditions in the presence of metal ions is one of the plausible triggers of the emergence of life. The salt-induced peptide formation reaction has been suggested as being prebiotically relevant and was examined for the formation of peptides in NaCl solutions. In previous work we have argued that the first protocell could have emerged in KCl solution. Using HPLC-MS/MS analysis, we found that K+ is more than an order of magnitude more effective in the L-glutamic acid oligomerization with 1,1'-carbonyldiimidazole in aqueous solutions than the same concentration of Na+, which is consistent with the diffusion theory calculations. We anticipate that prebiotic peptides could have formed with K+ as the driving force, not Na+, as commonly believed.

Catalysis in the Primordial World

“…55 This kind of catalytic activity was also found for sodium and potassium ions, 29 but the systematic study of the influence of pH, temperature, and metal concentration on the polymerization of glycine revealed a negative influence of other divalent metals. 62 , which have virtually no influence.…”

“…It was namely demonstrated that in 1 M concentration, they catalyse polymerization of glutamic acid with 1,1'-carbonyldiimidazole into 9-(Na + ) and 11-mer (K + ) oligopeptides. 29 More important, however, is that simple dipeptides Ser-His and Gly-Gly (less efficiently) catalyse polymerization of amino-acid esters, peptide fragments, and building blocks of peptide nucleic acids (PNA). 30 Basic peptides, polymers of lysine, catalyse hydrolysis of phosphodiester bond, especially if their conformation is β-sheet rather than random coil.…”

Computer Simulation of Amino Acid Oligomerization in Aqueous Solutions Induced by Condensing Agent

“…The formation of oligomers of the amino acid L-Glu in aqueous solutions induced through sodium and potassium salts during the activation of growth with CDI condensing agent has been previously examined [8]. The results showed that the dependence of the oligomer chain distribution in length ( means the number of monomers in the oligomer) depends on the type of solution (where = Na, K, O with sodium and potassium ions and without ions, resp.)…”

Application of de novo sequencing tools to study abiogenic peptide formations by tandem mass spectrometry. The case of homo‐peptides from glutamic acid complicated by substitutions of hydrogen by sodium or potassium atoms

“…For a model abiogenic peptide formation reaction, 1,1'‐carbonyldiimidazole was proposed as an efficient dehydration agent . Recently, we have reported that potassium chloride has more than an order of magnitude greater catalytic effect than the same concentration of sodium chloride on amino acid condensation in aqueous solution with carbonyldiimidazole . Interestingly, peptides obtained by different model reactions with amino acid mixtures conserve several sequence motifs (i.e.…”

“…Peptides synthesized in experiments of abiogenic peptide formation are not likely to occur in the existing databases so the only way to their identification by MS/MS spectra is de novo sequencing. [15,23] Previously, using UV-LC and MS analysis we have shown that potassium ions have more than an order of magnitude greater catalytic effect than sodium ions in a reaction of peptide formation with carbonyldiimidazole, [6] but no detailed structural characterization was done. Here we present a mass spectrometric study of carbonyldiimidazolecatalyzed oligomerization of glutamic acid in different environments: with 1 M sodium or potassium chloride and without salts.…”