Figure 3.

(a) Representation of eumelanin molecule in 3D. Red atoms are oxygen, while blue are nitrogen. The representation shows the stacking of the molecules, with the interplanar distance observed in this study. Also, the high of the triple-stacked eumelanin monomer is shown with an estimated value of 8.3 Å, which is compatible with three stacked molecules. (b) Proposed eumelanin superior order, where a few groups of three stacked protomolecules are ordered with an 8.1 Å periodicity. (c) Air/water interface showing the proposed ordering of the membranes and the protomolecule clusters seeding on the membranes. The angle of ∼30° is marked as measured by X-ray diffraction Ψ-scans.