Characterisation of the Pleurotolysin MACPF Pore Assembly KONDOSSTEPHANIE CATHERINE 2019 MACPF pore-forming proteins 'punch holes' in cell membranes, as part of their role in immune defence or microbial invasion. However, due to a small number of pore structures, our understanding of how these proteins form pores is incomplete. In this PhD, the structural characterisation of pleurotolysin, a MACPF from the oyster mushroom, was conducted. Structures were determined for pleurotolysin as a single subunit and as an assembled, multi-subunit pore complex. Furthermore, structures were obtained of non-inserted complexes, 'trapped' by molecular pins that tethered the regions responsible for pore formation in place. Together, these structures form snap-shots of how MACPF proteins form pores.