3-D reconstruction of 10S smooth muscle myosin. Electron Microscopy Databank accession code EMD-20084. (A–C) Front, back, and side views, respectively. (D–F) D–F correspond to A–C, with colors indicating different components of the structure. Blocked head is red; free head, green; tail segments 1 and 3, cyan; segment 2, magenta. In E, yellow circle indicates putative location of missing segment 1 density (see Fig. S3); red arrow, start of segment 3. Yellow star in D indicates the second hinge point.