School of Chemistry, Australian Centre for Astrobiology, ARC Centre of Excellence in Synthetic Biology, UNSW RNA Institute, UNSW Sydney, NSW 2052, Australia.
Laboratory of Biology and Information Science, School of Life Sciences, East China Normal University, Shanghai, 200062, P. R. China.
Small Methods. 2023 Dec;7(12):e2300126. doi: 10.1002/smtd.202300126. Epub 2023 May 28.
Vesicle fusion is an important process underlying cell division, transport, and membrane trafficking. In phospholipid systems, a range of fusogens including divalent cations and depletants have been shown to induce adhesion, hemifusion, and then full content fusion between vesicles. This work shows that these fusogens do not perform the same function for fatty acid vesicles, which are used as model protocells (primitive cells). Even when fatty acid vesicles appear adhered or hemifused to each other, the intervening barriers between vesicles do not rupture. This difference is likely because fatty acids have a single aliphatic tail, and are more dynamic than their phospholipid counterparts. To address this, it is postulated that fusion could instead occur under conditions, such as lipid exchange, that disrupt lipid packing. Using both experiments and molecular dynamics simulations, it is verified that fusion in fatty acid systems can indeed be induced by lipid exchange. These results begin to probe how membrane biophysics could constrain the evolutionary dynamics of protocells.
囊泡融合是细胞分裂、运输和膜运输的重要过程。在磷脂系统中，已经证明包括二价阳离子和去溶剂化剂在内的一系列融合剂可诱导囊泡之间的黏附、半融合，然后是完全内容物融合。这项工作表明，这些融合剂对脂肪酸囊泡不起作用，脂肪酸囊泡被用作模型原细胞（原始细胞）。即使脂肪酸囊泡彼此黏附或半融合，囊泡之间的中间屏障也不会破裂。这种差异可能是因为脂肪酸只有一个脂肪族尾部，比它们的磷脂对应物更具动态性。为了解决这个问题，有人假设融合可能在破坏脂质堆积的条件下发生，例如脂质交换。通过实验和分子动力学模拟，验证了脂肪酸体系中的融合确实可以通过脂质交换来诱导。这些结果开始探讨膜生物物理学如何限制原细胞的进化动力学。
