Figure 2. Myosin II stuctures.   (A) Functional myosin II is a hexamer with two heavy chains and four light chains. The heavy chain globular heads (motor domains) are on top. Each heavy chain neck is decorated with two light chains. The long coiled-coil tails are ~1600 angstroms in length.   (B) Thick and thin filaments in the sarcomere. (C) Magnified view of the head region of a myosin II hexamer. Paintings by David S. Goodsell of The Scripps Research Institute. PDB ID: 1b7t. Public domain source: Myosin, Molecule of the Month at www.pdb.org.