Amino acid activation with adenosine 5′-phosphorimidazolide

Abstract

Amino acids are activated by reaction with adenosine 5'-phosphorimidazolide in aqueous imidazole buffers. If adenosine 5'-(O-methylphosphate), an analogue of the 3'-terminus of t-RNA is present, 2'(3')-O-aminoacyladenosine 5'-(O-methylphosphate) is formed. Fifteen percent of this compound accumulated at pH 5.8, but less was formed at higher pHs. The highest efficiency of utilization if ImpA attained in our experiments was about 24%. Analogous reactions occured with several other amino acids, including a number that have functional side-chains.

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

“…Experiments to detect these other products are underway; preliminary results indicate that significant amounts of both diketopiperazines and histidyl-bound glycine are formed, but that the turnover numbers observed for the catalyst are not greatly altered. The mechanism of catalysis by histidyl-histidine can be postulated by reference to the fact that imidazole is known to participate in acyl transfer reactions in a number of cases involving amino acids (Weber and Lacey 1974;Weber et al 1977;Weber and Orgel 1978;Lohrmann and Orgel 1973 ;Ehler and Orgel 1976). The cycling reaction on the clay surface may provide activated amino acyl groups (White and Erickson 1980) which could react with the imidazole ring of a histidine residue to produce an amino acid imidazolide.…”

Nitrogenous Derivatives of Phosphorus and the Origins of Life: Plausible Prebiotic Phosphorylating Agents in Water

“…In the late 70s, Orgel et al published several studies regarding the formation of dipeptide where the first amino acid was attached via the carboxylic moiety to the 2'(3')-hydroxyl of a 5'-methyl phosphate adenosine (MepA-Gly 61 , Figure 12 ) by the reaction of the –COOH part of the amino acid with the phosphoroimidazolide intermediate of adenosine (ImpA) 55 leading to the activation of the carboxylic acid that could further react with the free hydroxyl of the ribonucleoside [ 52 , 53 ]. However, this water-soluble intermediate 61 mostly led to the formation of diketopiperazine.…”

“… Introduction of imidazole 5'-adenosine monoamidophosphate (ImpA) 55 for the activation of amino acid residues to form longer peptides as demonstrated by Orgel et al [ 52 , 53 ]. …”

Ribonucleotides and RNA Promote Peptide Chain Growth

“…[14] Covalent attachment of ap eptide to an RNAs trand prevents the loss of the precious oligomer through diffusion and favors complex formation. [15,16] Even today,g rowing polypeptides are covalently linked to RNAduring translation as peptidyl tRNAs.Ideally, an experimental set-up used to search for primordial peptidyl RNAs should run without the need for separate chemical steps,s uch as the ex situ activation of nucleotides or amino acids, [17,18] or the esterification of tRNAm odel compounds. [15,16] Even today,g rowing polypeptides are covalently linked to RNAduring translation as peptidyl tRNAs.Ideally, an experimental set-up used to search for primordial peptidyl RNAs should run without the need for separate chemical steps,s uch as the ex situ activation of nucleotides or amino acids, [17,18] or the esterification of tRNAm odel compounds.…”