prefusion
Prefusion refers to the state of a membrane protein before it has undergone its final conformational change to become fusion-competent. This is a critical stage in processes involving membrane fusion, such as viral entry into host cells or the fusion of organelles within a cell. In this prefusion conformation, the protein typically adopts a relatively stable structure that is distinct from its postfusion state. This prefusion state is often characterized by exposed regions that will later be involved in interacting with a target membrane or in undergoing significant structural rearrangements.
The transition from the prefusion state to the postfusion state is usually triggered by specific environmental