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Figure 4
(a) Atomic models derived from the two CD59-inhibited MAC complexes: CD59-C5b8 and CD59-C5b9. Complement proteins coloured: C5b (orange), C6 (red), C7 (purple), C8 (blue) and C9 (turquoise); CD59 in cyan. The position of the membrane relative to the models is indicated as double black lines. (b) Ribbon diagram showing the intermolecular anti-parallel β-sheet formed between CD59 (cyan) and C8α (blue). The inset highlights the hydrogen-bonding network of the backbone interactions within the β-sheet. [(c), left panel] CD59 (cyan) deflects the β-hairpins of C8α (blue) 30° from their trajectory towards the membrane. CD59:Y62, which is important for both MAC inhibition and bacterial pore formation, is highlighted in sticks representation. [(c), right panel] CD59 sterically blocks the membrane trajectory of two C9 molecules' β-hairpins (C9, turquoise), deflecting them 60° from their MAC conformation.

IUCrJ
Volume 13| Part 3| May 2026| Pages 221-227
ISSN: 2052-2525
https://doi.org/10.1107/S2052252526002927