Figure 7.

Possible conformational changes of αIIb upon binding of Ca²⁺-CIB1. (A) Superposition of the ordered structural fragment (983–995) of the averaged structure of αIIb-L complexed with Ca²⁺-CIB1 with the corresponding fragment of 2KNC. A steric clash was observed between 2KNC and the 8th helix of Ca²⁺-CIB1 (H8, brown color); The N-terminal extension of Ca²⁺-CIB1 (H0, pink color) points toward the cell membrane, which is consistent with its role of linking the myristoyl group and the Ca²⁺-CIB1 to a membrane. (B) The side view of (A); (C) a possible bending mechanism was proposed for the conformational change of αIIb upon binding of Ca²⁺-CIB1, as indicated by the red dashed line with arrows. The letter N in italics indicates the N-terminal of Ca²⁺-CIB1.