Fig. 4.

Schematic diagram of domain rearrangements and flexibility in C3 products. The positions of domains are schematically represented. The CUB domain in C3(N) and C3b is shown with a dashed outline, because it did not provide clear density in EM class averages. The unfolded N-terminal portion of the CUB segment in iC3b is shown as a blue line. The range of mobility of the key ring moiety relative to the TED is represented with orange arrows. (N) represents nucleophiles added to the thioester including H₂O and CH₃NH₂.