Figure 2.

Comparison of the independent Fc∊3-4 and derCD23 molecules of the two crystal forms of the derCD23–Fc∊3-4 complex. (a) Superposition of the four Ca²⁺-free derCD23–Fc∊3-4 interactions in the triclinic crystal form. [The interacting chains (Fc∊34:CD23) A:E, B:F, C:G and D:H are coloured as in Fig. 1 ▶ and are superposed on the C∊4 and derCD23 domains.] (b) Superposition of the six Ca²⁺-free derCD23–Fc∊3-4 interactions in the orthorhombic crystal form (PDB entry 4ezm). [The interacting chains (Fc∊3-4:CD23) A:G, B:H, C:I, D:J, E:K and F:L are coloured red, orange, yellow, green, indigo and blue, respectively, and are superposed on the C∊4 and derCD23 domains.] (c) Superposition of the six Ca²⁺-bound derCD23–Fc∊3-4 interactions in the orthorhombic crystal form [PDB entry 4gko; same colouring scheme as in (b)]. (d) Superposition of Fc∊3-4 chains C (yellow) and D (green) of the Ca²⁺-free orthorhombic crystal form with chain C (pink) of the triclinic form (superposed on the C∊4 domains).