A. Structure and domain organization of the motor domain of cytoplasmic dynein (PDB 4RH7 Inset shows zoom of MTBD (white) and coiled-coil stalk (grey), which consist of two helices, CC1 and CC2. Well conserved residues, that were used as anchor points to define CC1 and CC2 in this study are depicted as red spheres. Numbering is based on yeast cytoplasmic dynein. 