Oxazolone mediated peptide chain extension and homochirality in aqueous microdroplets

• 成果类型: Article
• 署名作者: Qiu, Lingqi; Cooks, Graham
• 署名单位: Purdue University System; Purdue University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9586
• DOI: 10.1073/pnas.2309360120
• 发表日期: 2024-01-09
• 关键词: amide bond formation; atmospheric aerosols; amino-acids; water; origin; surface; polypeptides; interfaces; chemistry; crystals

摘要

Peptide formation from amino acids is thermodynamically unfavorable but a recent study provided evidence that the reaction occurs at the air/solution interfaces of aqueous microdroplets. Here, we show that i) the suggested amino acid complex in microdrop-lets undergoes dehydration to form oxazolone; ii) addition of water to oxazolone forms the dipeptide; and iii) reaction of oxazolone with other amino acids forms tripeptides. Furthermore, the chirality of the reacting amino acids is preserved in the oxazolone product, and strong chiral selectivity is observed when converting the oxazolone to tripeptide. This last fact ensures that optically impure amino acids will undergo chain extension to generate pure homochiral peptides. Peptide formation in bulk by wet -dry cycling shares a common pathway with the microdroplet reaction, both involving the oxazolone intermediate.