Movie S1.

Interaction of JAS with PfAct1. (A) JAS (yellow) binds in regular distances inside the actin filament (gray). (B) Close-up view of the central JAS molecule. JAS binds noncovalently to three actin subunits, strengthening both interstrand and intrastrand contacts. (C) JAS snugly fits into a complementarily shaped groove formed by the interface of SD4 of one subunit (blue) and SD3 of the adjacent intrastrand subunit (cyan). Its cyclic ring stacks onto a plateau formed by residues 198–202 of SD4 of the first subunit (blue). The aromatic side chains of JAS enter between the two strands, separating SD4 of the same subunit (blue) and SD1 of the opposing interstrand subunit (magenta). (D) Same view as in Fig. 3B.