1.C.36.1.1
IIITCP protein complex EspB/EspD (SctBE). The topology of and EspD interaction sites in EspB have been defined (Luo and Donnenberg, 2011).  EspD inserts into the membrane with its two helical hairpins traversing the membrane with the N- and C-termini on the extraluminal surface, forming 2.5 diameter pores (Chatterjee et al. 2015).  EspD (SctE) plays a dominant role in pore formation as it assembles into an oligomeric state, regardless of pH, membrane contact, or the presence of EspB (SctB). Subsequently, EspB subunits integrate into EspD homo-oligomers to create EspB-EspD hetero-oligomers that adopt a transmembrane orientation to create a functional pore complex (Gershberg et al. 2024).