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 Camidated
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.
Interactions between Copper-binding Sites Determine the Redox Status and Conformation of the Regulatory N-terminal Domain of ATP7B
