A schematic drawing showing the possible fit of inside of spinach c14-ring with plastoquinone (PQ-9) molecules. (A) View from stroma side. PQ-9 molecules are colored cyan and shown as spheres. (B) Side view of the c14-ring with hydrophobic area inside fitted with PQ-9 molecules. PQ-9 molecules are oriented in different directions and are shown with sticks. (C) View from lumen side. C-ring is shown in surface representation. The surface is colored according to the hydrophobicity of amino acids (see legend on the right).