Successive HS-AFM images of F-actin–HMM complex in the presence of 0.2 μM ATP. (a) Double-headed HMM motors bound between two actin filaments in ∼37 nm distance to form a stable structure with up to eight individual myosin heads (four HMM molecules), attached by their S2 regions. (b) HMM heads between two actin filaments highlighted by red colors, S2 region of the HMM molecules highlighted by green color. (c) High-contrast images from a to highlight the connected S2 regions between HMM molecules. Numbers indicate the time in seconds, scan rate: 14.4 fps, scale bar, 30 nm.