Figure 1 : Domain organization in LLO.

From: Engineering a pH responsive pore forming protein

Figure 1

(a) Schematic drawing of LLO bound to the lipid membrane. The protein and the membrane are drawn to scale. LLO associates with the membrane with D4 (magenta), D2 (yellow) connects D4 to the pore-forming D1 (green) and D3 (grey) domains. D3 contains the HB1 (light brown cylinders) and HB2 (blue cylinders) that unwind and form transmembrane hairpins during pore formation. Majority of CDCs require relatively high concentrations of cholesterol (orange) in the membranes. (b) Crystal structure of LLO (PDB ID: 4CDB) in ribbon representation, the residues mutated in this study are in the central part of the molecule (in D2 and D3) and depicted as sticks. (c) Close up of D2-D3 interface in (b). The pH sensor (acidic triad D208, E247, D320; green sticks) is located in D3, between the central β-sheet and HB2.