3.4.21.43	crystal structures of the C3b homologue cobra venom factor CVF in complex with C5, and in complex with C5 and the inhibitor SSL7, both at 4.3 A resolution. The structures reveal a parallel two-point attachment between C5 and CVF, where the presence of SSL7 only slightly affects the C5-CVF interface, explaining the IgA dependence for SSL7-mediated inhibition of C5 cleavage. CVF functions as a relatively rigid binding scaffold inducing a conformational change in C5, which positions its cleavage site in proximity to the serine protease Bb	
3.4.21.43	Mg2+-bound C2a, hanging drop vapor diffusion method, 22°C, 0.002 ml of 20 mg/ml protein solution is mixed with 0.002 ml of well solution containing 20% w/v polyethylene glycol 10000, 0.1 M HEPES, pH 7.5, and 0.0004 ml of 0.3 M glycyl-glycyl-glycine, 3-7 days, X-ray diffraction structure determination and analysis at 1.9-2.3 A resolution	
3.4.21.43	N-terminal segment C2b, by the hanging-drop vapor-diffusion method, to 1.8 A resolution. Space group P31 with unit-cell parameters a=b= 60.09 A and c = 61.69 A. Conformational changes of C2, C2a and C2b during C3 convertase C4bC2a formation