NR AKUQ
AU Shiraishi,N.; Ohta,Y.; Nishikimi,M.
TI The octapeptide repeat region of prion protein binds Cu(II) in the redox-inactive state
QU Biochemical and Biophysical Research Communications 2000 Jan 7; 267(1): 398-402
PT journal article
AB The octapeptide repeat region of human prion protein is known to bind four Cu(II) ions per molecule. A peptide, Octa(4), representing this region was tested for inhibitory effects on copper-catalyzed oxidation of l-ascorbate or glutathione and on generation of OH(*) during the former reaction. The result indicated that the catalytic activity of the first Cu(II) ion bound to an Octa(4) molecule was completely suppressed. The valence state of the copper under reducing conditions was Cu(II), as determined by a newly developed method using bathocuproinedisulfonate under acidic conditions. Furthermore, it was shown that Escherichia coli cells expressing the octapeptide repeat region were significantly resistant to copper treatment compared with control cells. The results taken together indicate that prion protein can function to sequester copper ions in the redox-inactive state, rendering copper-induced generation of reactive oxygen species impossible.
MH Ascorbic Acid/metabolism; Binding Sites; Cloning, Molecular; Copper/*metabolism; Escherichia coli; Glutathione/metabolism; Human; Kinetics; Oxidation-Reduction; Peptide Fragments/chemistry/metabolism; Prions/*chemistry/*metabolism; Recombinant Proteins/metabolism; Repetitive Sequences, Amino Acid
AD Department of Biochemistry, Wakayama Medical College, Wakayama, 641-0012, Japan.
SP englisch
PO USA