(A) Ribbon diagram of T417I,Δ418,419 KIT D4D5 dimer. D4 and D5 of one protomer are colored in purple and blue, and D4, D5 of another protomer are in orange and green respectively. N and C termini are labeled. Ile 417, an oncogenic mutation, is marked with a red balls. (B) Surface representation of T417I,Δ418,419 KIT D4D5 dimer. Upper panel shows a view following 90° rotation along the horizontal axis of the view shown in the bottom panel. Color coding is the same as in panel A. 2 fold symmetry axis is shown as vertical line passing through the middle of “V”.