Before revision: This region belongs to the N-terminal unstructured region ( 1-123 ) of prion proteins , the structure of which has proved hard to determine using NMR spectroscopy or X-ray crystallography due to the insoluble and noncrystalline nature of the amyloid fibril .
After revision: This region belongs to the N-terminal unstructured region ( 1-123 ) of prion proteins . Many experimental studies have shown that the AGAAAAGA region has amyloid fibril forming properties and plays an important role in prion diseases. However, due to the insoluble and noncrystalline nature of the amyloid fibril .