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The leading European journal for inorganic and organometallic chemistry
Paper
J. Chem. Soc., Dalton Trans., 2002, 2269 - 2274, DOI: 10.1039/b201040m
Is the monomeric prion octapeptide repeat PHGGGWGQ a specific ligand for Cu2+ ions?
Marek 
uczkowski, Henryk Kozlowski, Maciej Stawikowski, Krzysztof Rolka, Elena Gaggelli, Daniela Valensin and Gianni Valensin
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 3Gly and 4Gly 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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