Figure 3

NcdT436S crystal structure. A, NcdT436S heads are oriented asymmetrically relative to the coiled-coil stalk. Chain A, cyan; chain B, green. B, Wild-type Ncd (PDB 1CZ7) [17] heads show two-fold symmetry around the axis of the stalk. Bottom, structures rotated 90°; the stalk extends out of the plane of the page highlighting the different orientation of the chain B head.