 To date atomic structures have been determined for CCPs 1–3, CCP 5, CCP 7 (both 402H & 402Y), CCPs 10–11 and CCPs 11–12, CCPs 12–13, CCP 15, CCP 16, CCPs 15–16, CCPs 18–20, and CCPs 19–20.The atomic structure for CCPs 6–8 (402H) bound to the GAG mimic sucrose octasulfate, CCPs 1–4 in complex with C3b and CCPs 19–20 in complex with C3d (that corresponds to the thioster domain of C3b) have also been determined.Although an atomic resolution structure for intact factor H has not yet been determined, low resolution techniques indicate that it may be bent back in solution.