The process in which proteins mediate their own secretion across the outer membrane through a beta-barrel pore structure formed by the C-terminal domain of the protein precursor. Following passage across the outer membrane, the mature protein is released from the pore by an autocatalytic activity. Proteins secreted by the Type V system are first translocated across the plasma membrane by the Sec pathway.

The space external to the outermost structure of a cell. For cells without external protective or external encapsulating structures this refers to space outside of the plasma membrane. This term covers the host cell environment outside an intracellular parasite.

A lipid bilayer that forms the outermost membrane of the cell envelope; enriched in polysaccharide and protein; the outer leaflet of the membrane contains specific lipopolysaccharide structures.