Computational modelling of toroidal membranes at division and fission sites

The formation of specialised membrane architectures is fundamental to biological processes. Computational modelling of membrane structures offers a means to unravel complex molecular mechanisms that remain inaccessible through in vitro or in vivo approaches. Among these architectures, toroidal membranes, otherwise known as fusion pores or fission pores, occur during the final stages of cell division, exocytosis, endocytosis, and membrane fission; including during the phagocytic-like engulfment of bacterial endospores. Here we have designed 'MemTorMD', a computational simulation pipeline based on the 'Triangulated Surface to Coarse Grain' (TS2CG) methodology, to enable coarse-grained modelling of free toroidal membranes with biologically relevant dimensions. This approach allowed us to overcome the hurdles and determine the lipid properties required for stable toroidal membrane formation, thus providing a biologically accurate simulation surface. Furthermore, we demonstrate the applicability of this approach to investigate the function of proteins that localise at toroidal membranes and drive molecular events such as membrane fission, by a prokaryotic fission protein. Collectively, our work using coarse grained molecular simulations provides insight into the simulation of biologically accurate toroidal membranes, as well as protein behaviour at toroidal membranes, and offers a computational platform for further development of more complex simulations involving additional molecular components at toroidal membranes present in a range of processes across life.