Before revision: To date , there is little structural data available on the AGAAAAGA palindrome in the hydrophobic region (113-120) of prion proteins  , although many experimental studies have shown that this region has amyloid fibril forming properties .
After revision: X-ray crystallography is a powerful tool to determine the protein 3D structure. However, it is time-consuming and expensive, and not all proteins can be successfully crystallized, particularly for membrane proteins. Although nuclear magnetic resonance (NMR) spectroscopy is indeed a very powerful tool in determining the 3D structures of membrane proteins, it is also time-consuming and costly. To the best of the authors' knowledge , there is little structural data available on the AGAAAAGA palindrome in the hydrophobic region (113-120) of prion proteins , although many experimental studies have shown that this region has amyloid fibril forming properties .