5687-48-9Relevant articles and documents
Peptide ligation by chemoselective aminonitrile coupling in water
Canavelli, Pierre,Islam, Saidul,Powner, Matthew W.
, p. 546 - 549 (2019/07/18)
Amide bond formation is one of the most important reactions in both chemistry and biology1–4, but there is currently no chemical method of achieving α-peptide ligation in water that tolerates all of the 20 proteinogenic amino acids at the peptide ligation site. The universal genetic code establishes that the biological role of peptides predates life’s last universal common ancestor and that peptides played an essential part in the origins of life5–9. The essential role of sulfur in the citric acid cycle, non-ribosomal peptide synthesis and polyketide biosynthesis point towards thioester-dependent peptide ligations preceding RNA-dependent protein synthesis during the evolution of life5,9–13. However, a robust mechanism for aminoacyl thioester formation has not been demonstrated13. Here we report a chemoselective, high-yielding α-aminonitrile ligation that exploits only prebiotically plausible molecules—hydrogen sulfide, thioacetate12,14 and ferricyanide12,14–17 or cyanoacetylene8,14—to yield α-peptides in water. The ligation is extremely selective for α-aminonitrile coupling and tolerates all of the 20 proteinogenic amino acid residues. Two essential features enable peptide ligation in water: the reactivity and pKaH of α-aminonitriles makes them compatible with ligation at neutral pH and N-acylation stabilizes the peptide product and activates the peptide precursor to (biomimetic) N-to-C peptide ligation. Our model unites prebiotic aminonitrile synthesis and biological α-peptides, suggesting that short N-acyl peptide nitriles were plausible substrates during early evolution.
Reactions of substituted aspirins with amino acids
Orth, Elisa S.,Medeiros, Michelle,Souza, Bruno S.,Caon, Natalia B.,Kirby, Anthony J.,Nome, Faruk
supporting information, p. 939 - 945 (2014/01/06)
Acyl transfers are key reactions in biology and in the laboratory. In biological systems they are involved in energy transport, in the assembly of complex molecules and in the mechanisms of efficient action of many hydrolytic enzymes. We report a mechanistic and calculational study of the selective N-acylation reactions of amino acids by substituted aspirins, under mild conditions, in water at 25 °C. The acetylated amino-acid products of the reactions were identified by nuclear magnetic resonance, and the reaction steps were studied by density functional theory. Copyright
Rates of uncatalyzed peptide bond hydrolysis in neutral solution and the transition state affinities of proteases
Radzicka,Wolfenden
, p. 6105 - 6109 (2007/10/03)
To assess the relative proficiencies of enzymes that catalyze the hydrolysis of internal and C-terminal peptide bonds, the rates of the corresponding nonenzymatic reactions were examined at elevated temperatures in sealed quartz tubes, yielding linear Arrhenius plots. The results indicate that in neutral solution at 25°C, peptide bonds are hydrolyzed with half-times of approximately 500 years for the C-terminal bond of acetylglycylglycine, 600 years for the internal peptide bond of acetylglycylglycine N-methylamide, and 350 years for the dipeptide glycylglycine. These reactions, insensitive to changing pH or ionic strength, appear to represent uncatalyzed attack by water on the peptide bond. Comparison of rate constants indicates very strong binding of the altered substrate in the transition states for the corresponding enzyme reactions, K(tx) attaining a value of less than 10-17 M in carboxypeptidase B. The half-life of the N-terminal peptide bond in glycylglycine N-methylamide, whose hydrolysis might have provided a reference for assessing the catalytic proficiency of an aminopeptidase, could not be determined because this compound undergoes relatively rapid intramolecular displacement to form diketopiperazine (t( 1/4 ) ~ 35 days at pH 7 and 37°C). The speed of this latter process suggests an evolutionary rationale for posttranslational N-acetylation of proteins in higher organisms, as a protection against rapid degradation.
