Bottacchiari Matteo, Gallo Mirko, Bussoletti Marco, Casciola Carlo Massimo
Department of Mechanical and Aerospace Engineering, Sapienza Università di Roma, Rome, Italy.
Present Address: School of Architecture, Technology and Engineering, University of Brighton, Brighton, United Kingdom.
Commun Phys. 2022;5(1):283. doi: 10.1038/s42005-022-01055-2. Epub 2022 Nov 12.
Topological transitions of fluid lipid membranes are fundamental processes for cell life. For example, they are required for endo- and exocytosis or to enable neurotransmitters to cross the neural synapses. Here, inspired by the idea that fusion and fission proteins could have evolved in Nature in order to carry out a minimal work expenditure, we evaluate the minimal free energy pathway for the transition between two spherical large unilamellar vesicles and a dumbbell-shaped one. To address the problem, we propose and successfully use a Ginzburg-Landau type of free energy, which allows us to uniquely describe without interruption the whole, full-scale topological change. We also compute the force fields needed to overcome the involved energy barriers. The obtained forces are in excellent agreement, in terms of intensity, scale, and spatial localization with experimental data on typical fission protein systems, whereas they suggest the presence of additional features in fusion proteins.
流体脂质膜的拓扑转变是细胞生命的基本过程。例如，胞吞作用和胞吐作用需要这些转变，或者使神经递质能够穿过神经突触也需要它们。在此，受融合蛋白和裂变蛋白可能在自然界中进化以实现最小功消耗这一观点的启发，我们评估了两个球形大单层囊泡与一个哑铃形囊泡之间转变的最小自由能路径。为了解决这个问题，我们提出并成功使用了一种金兹堡 - 朗道型自由能，它使我们能够不间断地唯一描述整个全尺度拓扑变化。我们还计算了克服相关能量障碍所需的力场。就强度、尺度和空间定位而言，所获得的力与典型裂变蛋白系统的实验数据高度吻合，而它们表明融合蛋白中存在其他特征。
