Noriyuki Shiraishi* and Yoshiaki Hirano Pages 1 - 10 ( 10 )
Background: It has been previously found that PrP23-98, which contains four highly conserved octarepeats (residues 60-91) and one partial repeat (residues 92-96), polymerizes into amyloid-like and proteinase K-resistant spherical aggregates in the presence of NADPH plus copper ions.
Objective: We aimed to determine the requirements for the formation of these aggregates.
Methods: In this study, we performed an aggregation experiment using N-acetylated and C-amidated PrP fragments of the N-terminal domain, Octa1, Octa2, Octa3, Octa4, PrP84−114, and PrP76−114, in the presence of NADPH with copper ions, and focused on the effect of the number of copper-binding sites on aggregation.
Results: Among these PrP fragments, Octa4, containing four copper-binding sites, was particularly effective in forming aggregates. We also tested the effect of other pyridine nucleotides and adenine nucleotides on the aggregation of Octa4. ATP was equally effective, but NADH, NADP, ADP, and AMP had no effect.
Conclusion: The phosphate group on the adenine-linked ribose moiety of adenine nucleotides and pyridine nucleotides is presumed to be essential for the observed effect on aggregation. Efficient aggregation requires the presence of the four octarepeats. These insights may be helpful in the eventual development of therapeutic agents against prion-related disorders.
PrP fragment, Octa4, aggregation, adenine nucleotide, pyridine nucleotide, copper ion
Department of Nutrition, Tokai Gakuen University, 2-901 Nakahira, Nagoya 468-8514, Department of Nutrition, Tokai Gakuen University, 2-901 Nakahira, Nagoya 468-8514