Ac-PHGGGWGQ-NH2, an octarepeat peptide fragment of prion, is a relatively effective ligand for Cu2+ ions. At a pH of about 7.4 the major binding sites involve the imidazole nitrogen and two amide nitrogens of (3)Gly and (4)Gly giving a CuH-2L species. The stability of the complex formed is similar to other peptides having a similar type of coordination. The NMR spectra indicate that in CuH-2L the complex side chain of the Trp residue is located very close to the metal ion. The geometry around the Cu2+ ion seems to be slightly distorted from the tetragonal one. In strongly basic solution the coordination involves an additional amide nitrogen. In CuH-2L, CuH-3L and CuH-4L complexes the amide nitrogens involved in the metal ion binding are those placed towards the C-terminal from the His residue. The N-terminal of the unprotected octapeptide is very effective in binding the Cu2+ ion although at high pH the imidazole nitrogen may not be involved in metal ion binding.
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|Titolo:||Is the monomeric prion octapeptide repeat PHGGGWGQ a specific ligand for Cu2+ ions?|
|Citazione:||Łuczkowski, M., Kozlowski, H., Stawikowski, M., Rolka, K., Gaggelli, E., Valensin, D., et al. (2002). Is the monomeric prion octapeptide repeat PHGGGWGQ a specific ligand for Cu2+ ions?. JOURNAL OF THE CHEMICAL SOCIETY. DALTON TRANSACTIONS, 11, 2269-2274.|
|Appare nelle tipologie:||1.1 Articolo in rivista|
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