Fig. 8. Binding of 6xHis-ABD to actin in vitro. (A) Cosedimentation of 10 µM 6xHis-ABD with 2.5 µM F-actin by ultracentrifugation. (B) Bundling of 10 µM actin in the presence of 6xHis-ABD analyzed by low-speed centrifugation. S, supernatant; P, pellet. Positions of ABD and actin are indicated on the right. (C) The effect on polymerization kinetics of 8 µM actin in the absence or presence of various amounts of 6xHis-ABD observed by the change in pyrenyl-actin fluorescence.