College for Life Sciences, Wissenschaftskolleg zu Berlin (Institute for Advanced Study, Berlin), Germany.
Bioessays. 2019 May;41(5):e1800251. doi: 10.1002/bies.201800251. Epub 2019 Apr 10.
Recent results from engineered and natural samples show that the starkly different lipids of archaea and bacteria can form stable hybrid membranes. But if the two types can mix, why don't they? That is, why do most bacteria and all eukaryotes have only typically bacterial lipids, and archaea archaeal lipids? It is suggested here that the reason may lie on the other main component of cellular membranes: membrane proteins, and their close adaptation to the lipids. Archaeal lipids in modern bacteria could suggest that the last universal common ancestor (LUCA) had both lipid types. However, this would imply a rather elaborate evolutionary scenario, while negating simpler alternatives. In light of widespread horizontal gene transfer across the prokaryotic domains, hybrid membranes reveal that the lipid divide did not just occur once at the divergence of archaea and bacteria from LUCA. Instead, it continues to occur actively to this day.
最近来自工程设计和自然样本的结果表明，古菌和细菌截然不同的脂质可以形成稳定的混合膜。但是，如果这两种类型可以混合，为什么它们不混合呢？也就是说，为什么大多数细菌和所有真核生物只有典型的细菌脂质，而古菌只有古菌脂质呢？这里提出的原因可能在于细胞膜的另一个主要成分：膜蛋白，以及它们与脂质的紧密适应。现代细菌中的古菌脂质表明最后的普遍共同祖先（LUCA）具有这两种脂质类型。然而，这将意味着一个相当复杂的进化场景，同时否定了更简单的替代方案。鉴于在原核域中广泛存在水平基因转移，混合膜表明脂质的划分并非仅在 LUCA 从古菌和细菌的分化时发生一次。相反，它今天仍在持续活跃地发生。
