In summary, we conclude that the X-ray diffraction is a useful
technique for comparing melanins from various sources and could
have usefulness in studying capsular polysaccharides. For instance,
we serendipitously observed a diffraction signal from cryptococcal
polysaccharide indicative of a repeating structure that could be
exploited in future studies to gain new structural insights. Our
results provide the first evidence that natural fungal melanins share
the basic stacked planar sheet structure proposed for other
melanins and indicate that fungal melanins can be identified by
their stacking peak parameters and appear to fall into groups
subclasses, perhaps related to their biosynthetic pathway differences.