Cysteine 144 is a key residue in the copper reduction by the beta-amyloid precursor protein.
The beta-amyloid precursor protein (beta-APP) contains a copper-binding site localized between amino acids 135 and 156 (beta-APP(135-156)). We have employed synthetic beta-APP peptides to characterize their capacities to reduce Cu(II) to Cu(I). Analogues of the wild-type beta-APP(135-156) peptide, containing specific amino acid substitutions, were used to establish which residues are specifically involved in the reduction of copper by beta-APP(135-156). We report here that beta-APP's copper-binding domain reduced Cu(II) to Cu(I). The single-mutant beta-APP(His147-->Ala) and the double-mutant beta-APP(His147-->Ala/His149-->Ala) showed a small decrease in copper reduction in relation to the wild-type peptide and the beta-APP(Cys144-->Ser) mutation abolished it, suggesting that Cys144 is the key amino acid in the oxidoreduction reaction. Our results confirm that soluble beta-APP is involved in the reduction of Cu(II) to Cu(I).
Ruiz
F H
FH
Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Santiago, Chile.
González
M
M
Bodini
M
M
Opazo
C
C
Inestrosa
N C
NC
D019943:Amino Acid Substitution; D016564:Amyloid beta-Protein Precursor / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D003545:Cysteine / Q000737:chemistry*; D006801:Humans; D009154:Mutation; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000737:chemistry; D011199:Potentiometry
D016564:Amyloid beta-Protein Precursor; D010446:Peptide Fragments; D003300:Copper; D003545:Cysteine