Graphical representation of the combined EF loop clustering of wild-type CH3 domain, Q418L/S424T, stem(0) and stem-(0). The EF loop of the central member structure of cluster 1 is shown in black. (A) Central member structure of cluster 1. (B) Superposition of central member structure EF loops for the structurally similar clusters 1, 2, 4, 5, 8, 9 and 10. (C) Superposition of central member structure EF loops for the structurally deviating clusters 3, 6 and 7.