Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747AG Groningen, Netherlands.
ACS Synth Biol. 2024 Aug 16;13(8):2470-2479. doi: 10.1021/acssynbio.4c00235. Epub 2024 Aug 3.
Membrane lipid chemistry is remarkably different in archaea compared with bacteria and eukaryotes. In the evolutionary context, this is also termed the lipid divide and is reflected by distinct biosynthetic pathways. Contemporary organisms have almost without exception only one type of membrane lipid. During early membrane evolution, mixed membrane stages likely occurred, and it was hypothesized that the instability of such mixtures was the driving force for the lipid divide. To examine the compatibility between archaeal and bacterial lipids, the bacterium has been engineered to contain both types of lipids with varying success. Only limited production of archaeal lipid archaetidylethanolamine was achieved. Here, we substantially increased its production in by overexpression of an archaeal phosphatidylserine synthase needed for ethanolamine headgroup attachment. Furthermore, we introduced a synthetic isoprenoid utilization pathway to increase the supply of isopentenyl-diphosphate and dimethylallyl diphosphate. This improved archaeal lipid production substantially. The archaeal phospholipids also served as a substrate for the cardiolipin synthase, resulting in archaeal and novel hybrid archaeal/bacterial cardiolipin species not seen in living organisms before. Growth of the strain with the mixed membrane shows an enhanced sensitivity to the inhibitor of fatty acid biosynthesis, cerulenin, indicating a critical dependence of the engineered strain on its native phospholipids.
与细菌和真核生物相比，古菌的膜脂化学性质显著不同。从进化的角度来看，这也被称为脂质分裂，反映在独特的生物合成途径上。当代生物几乎无一例外地只有一种膜脂。在早期的膜进化过程中，可能存在混合膜阶段，并且有人假设这种混合物的不稳定性是脂质分裂的驱动力。为了研究古菌和细菌脂质之间的兼容性，已经对细菌进行了工程改造，使其同时含有这两种脂质，但成功的程度各不相同。只能有限地生产出古菌脂质 archaeetidylethanolamine。在这里，我们通过过表达用于乙醇胺头部基团连接的古菌磷脂酰丝氨酸合酶，大大提高了 中 archaeetidylethanolamine 的产量。此外，我们引入了一种合成异戊二烯利用途径，以增加异戊烯二磷酸和二甲基烯丙基二磷酸的供应。这大大提高了古菌脂质的产量。古菌磷脂也可作为 的心磷脂合酶的底物，产生以前在活细胞中未见过的古菌和新型混合古菌/细菌心磷脂物种。具有混合膜的 菌株的生长对脂肪酸生物合成抑制剂 cerulenin 表现出增强的敏感性，这表明工程化的 菌株对其天然磷脂的依赖性至关重要。
