美国加州大学教授Devaraj Neal K.团队报道了半胱氨酸与短链硫酯自发反应的原始细胞。相关研究成果发表在2024年10月30日出版的国际学术期刊《自然—化学》。

所有已知的生命形式都是由细胞组成的，细胞的边界由脂质膜定义，脂质膜将细胞内容物与环境隔开并保护其免受环境影响。尚不清楚最早的生命形式是如何划分的。一些模型表明单链脂质（如脂肪酸）起作用，但形成的膜通常不稳定，特别是当由较短的烷基链（≤C8）制成时，这些烷基链可能在益生元地球上更为普遍。

该文中，研究人员发现氨基酸半胱氨酸可以自发地与两个短链（C8）硫酯反应形成二酰基脂质，产生原细胞样膜囊泡。三组分反应在水中使用低浓度的反应物快速发生。二氧化硅可以通过简单的静电机制催化原细胞的形成。

几种简单的氨基硫醇反应形成二酰基脂质，包括短肽。形成的原细胞与功能性核酶相容，这表明多个短链前体的偶联，可能在细胞的早期进化过程中提供了膜构建块。

附：英文原文

Title: Protocells by spontaneous reaction of cysteine with short-chain thioesters

Author: Cho, Christy J., An, Taeyang, Lai, Yei-Chen, Vzquez-Salazar, Alberto, Fracassi, Alessandro, Brea, Roberto J., Chen, Irene A., Devaraj, Neal K.

Issue&Volume: 2024-10-30

Abstract: All known forms of life are composed of cells, whose boundaries are defined by lipid membranes that separate and protect cell contents from the environment. It is unknown how the earliest forms of life were compartmentalized. Several models have suggested a role for single-chain lipids such as fatty acids, but the membranes formed are often unstable, particularly when made from shorter alkyl chains (≤C8) that were probably more prevalent on prebiotic Earth. Here we show that the amino acid cysteine can spontaneously react with two short-chain (C8) thioesters to form diacyl lipids, generating protocell-like membrane vesicles. The three-component reaction takes place rapidly in water using low concentrations of reactants. Silica can catalyse the formation of protocells through a simple electrostatic mechanism. Several simple aminothiols react to form diacyl lipids, including short peptides. The protocells formed are compatible with functional ribozymes, suggesting that coupling of multiple short-chain precursors may have provided membrane building blocks during the early evolution of cells.

DOI: 10.1038/s41557-024-01666-y

Source: https://www.nature.com/articles/s41557-024-01666-y