Fig. 3.

(A) Fitted crystal structures showing head pairs and S2 on successive crowns along one strand of the myosin filament. Head pairs in the 2,3,1 crown sequence are quite closely connected, whereas there is a distinct gap between crowns 1 and 2. (B) Head pairs on crowns 3 and 1 are connected through an interaction between the RLC of the blocked head on crown 3 and the motor domain of the free head on crown 1. The red arrowed star indicates the predicted position of serine 15 in human myosin RLC. (C) A different type of intermolecular connection is observed between crowns 3 and 2 that is mediated by an interaction between the ELC of the blocked head on crown 2 and the motor domain of the free head on crown 3. (D) No intermolecular interaction is seen between the head pairs in crowns 1 and 2. S2 is shown in red, and the bare zone is oriented vertically down in all views.