Catalysis of peptide bond formation by histidyl-histidine in a fluctuating clay environment

Abstract

The condensation of glycine to form oligoglycines during wet-dry fluctuations on clay surfaces was enhanced up to threefold or greater by small amounts of histidyl-histidine. In addition, higher relative yields of the longer oligomers were produced. Other specific dipeptides tested gave no enhancement, and imidazole, histidine, and N-acetylhistidine gave only slight enhancements. Histidyl-histidine apparently acts as a true catalyst (in the sense of repeatedly catalyzing the reaction), since up to 52 nmol of additional glycine were incorporated into oligoglycine for each nmol of catalyst added. This is the first known instance of a peptide or similar molecule demonstrating a catalytic turnover number greater than unity in a prebiotic oligomer synthesis reaction, and suggests that histidyl-histidine is a model for a primitive prebiotic protoenzyme. Catalysis of peptide bond synthesis by a molecule which is itself a peptide implies that related systems may be capable of exhibiting autocatalytic growth.

Room-Temperature Luminescence from Kaolin Induced by Organic Amines

“…The hygroscopic water content was 3-4%. The cation-exchange capacity (CEC) for the Fisher material was 1.03 meq/100 g, as reported by White and Erickson (1980). Their determination was made by exchange with 1 M NH4OH and analysis by atomic absorption of released cations.…”

Peptide‐dominated membranes preceding the genetic takeover by RNA: latest thinking on a classic controversy

“…During wet-dry cycling on clay, even dipeptides of histidyl-histidine showed some catalytic enhancement, (50) and certain lone-helix peptides can indeed self-assemble to biologically active transmembrane clusters, such as antimicrobial peptides, (51) or repetitive model peptides [Ac-(LSSLLSL) 3 -CONH 2 ] surrounding a central channel. (52,53) Similarly, polar pockets drawn partly into the lipophilic core of a prebiotic membrane could have constituted the first metabolically active protoenzymes.…”

Diketopiperazine-mediated peptide formation in aqueous solution

“…A number of experiments concerning prebiotic peptide formation have been performed under various conditions with amino acids, though some of which seem to have been possible only at special areas on the primitive Earth, or by the use of amino acid derivatives or activated amino acids (Harada and Fox, 1958;Fox and Harada, 1960;Guidry, 1960, 1961;Paecht-Horowitz and Katchalsky, 1967;Lewinsohn et al, 1967;Sawai and Orgel, 1975;Nooner et al, 1977;Orgel, 1978, 1979a, b;White and Erickson, 1980;Yanagawa et al, 1984;Yanagawa and Kojima, 1985). However, it seems more likely to us that the chemical evolution might have taken place in the primitive oceans as a more universal place where peptides were formed from amino acids with an aid of various condensing agents and were accumulated gradually against their hydrolysis under mild conditions.…”