Coordination of copper(II) ions by the 11-20 and 11-28 fragments of human and mouse beta-amyloid peptide.
A potentiometric and spectroscopic (UV-vis, CD and EPR) study of Cu(II) binding to the (11-20), (11-28), (Ac-11-20H) and (Ac-11-28) fragments of human (H) and mouse (M) beta-amyloid peptide was carried out. The values of the protonation constants of the two lysine side chain amino groups for the (11-28) and (Ac-11-28) fragments of beta-amyloid peptide differ noticeably suggesting considerable interactions between the two residues. The N-terminal amino acid sequence Xaa-Yaa-His for the (11-20H) and (11-28H) fragments determines the coordination ability of the fragments studied to copper(II) ions. Addition of the (17-20) and (17-28) sequences to the (11-16) fragment of human and mouse beta-amyloid peptide does not change the coordination mode, and the stabilities of the complexes formed are comparable to those of the (11-16) peptide, although 1N complexes of the (11-28) fragments are stabilized by about one order of magnitude compared to those of the (11-16) peptides. The (Ac-11-28) peptides form complexes with the same coordination mode as those for the (Ac-11-16) fragments. The stability of the complexes for the (Ac-11-28H) fragment is one or two orders of magnitude higher compared to those of the (Ac-11-16H) fragment. This stabilization may result from structural organization of a peptide in copper(II) complexes.
Kowalik-Jankowska
Teresa
T
Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, Wroclaw, Poland. terkow@wchuwr.chem.uni.wroc.pl
Ruta-Dolejsz
Monika
M
Wiśniewska
Kornelia
K
Lankiewicz
Leszek
L
D000544:Alzheimer Disease / Q000378:metabolism; D000595:Amino Acid Sequence; D016229:Amyloid beta-Peptides / Q000737:chemistry*; D000818:Animals; D003300:Copper / Q000032:analysis*; D004795:Enzyme Stability; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000737:chemistry*; D011485:Protein Binding; D011522:Protons
D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; D011522:Protons; D003300:Copper