The dimeric and tetrameric octarepeat fragments of prion protein behave differently to its monomeric unit.
Potentiometric and spectroscopic data have shown that octarepeat dimer and tetramer are much more effective ligands for Cu(II) ions than simple octapeptide. Thus, the whole N-terminal segment of prion protein due to cooperative effects, could be more effective in binding of Cu(II) than simple peptides containing a His residue. The gain of the Cu(II) binding by longer octarepeat peptides derives from the involvement of up to four imidazoles in the coordination of the first Cu(II) ion. This type of binding increases the order of the peptide structure, which allows successive metal ions for easier coordination.
Valensin
Daniela
D
Department of Chemistry, University of Siena, via Aldo Moro, I-53100 Siena, Italy. valensin@unisi.it
Luczkowski
Marek
M
Mancini
Francesca Maria
FM
Legowska
Anna
A
Gaggelli
Elena
E
Valensin
Gianni
G
Rolka
Krzysztof
K
Kozlowski
Henryk
H
D001665:Binding Sites; D002413:Cations, Divalent; D003300:Copper / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D008024:Ligands; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D010446:Peptide Fragments / Q000737:chemistry*; D011328:Prions / Q000737:chemistry*; D011487:Protein Conformation; D020449:Repetitive Sequences, Amino Acid
D002413:Cations, Divalent; D008024:Ligands; D010446:Peptide Fragments; D011328:Prions; D003300:Copper