title: Copper binding to prion octarepeat peptides, a combined metal chelate affinity and immunochemical approaches.
abstract: Based on the hypothetical proposal of Sulkowski [E. Sulkowski, FEBS Lett. 307 (2) (1992) 129] for the implication of transition metal ions in the structural changes/oligomerisation of normal cellular prion protein (PrPc) resulting in the pathological isoform (PrPsc), we focused our study on the octarepat domain of this protein which has been supposed to be the metal binding site. We have studied the copper binding to synthetic prion octarepeat peptides (PHGGGWGQ)n (n=1, 3, 6) using metal chelate and size-exclusion modes of chromatographies. This copper binding induces oligomerisation resulting in multiple aggregates. Moreover, heterogeneity of metal bound octarepeat oligomers by ESI-MS has been demonstrated. In addition, anti prion antibodies specific to the octarepeat region were used to discriminate between metal free and copper, nickel and zinc bound hexamer octarepeat peptide. Differential recognition of Cu(II) and Zn(II) bound complexes has been observed which signify differences in exposed epitopes of aggregated peptides.
authors.affiliation: Laboratoire d'Interactions Moléculaires et de Technologie de Séparation (LIMTechS), Centre de Recherche de Royallieu, BP 20.529 Université de Technologie de Compiègne, F-60205 Compiègne Cedex, France.
authors.forename: Daniela
authors.initials: D
authors.lastname: Todorova-Balvay
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Simon
authors.forename: Christophe
authors.initials: C
authors.lastname: Créminon
authors.forename: Jacques
authors.initials: J
authors.lastname: Grassi
authors.forename: Thamarapu
authors.initials: T
authors.lastname: Srikrishnan
authors.forename: Mookambeswaran A
authors.initials: MA
authors.lastname: Vijayalakshmi
mesh_terms: D000937:Antigen-Antibody Reactions; D001665:Binding Sites; D002614:Chelating Agents; D002846:Chromatography, Affinity / Q000379:methods*; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003300:Copper / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D009532:Nickel / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D011328:Prions / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D011487:Protein Conformation / Q000187:drug effects; D020836:Protein Structure, Quaternary; D021241:Spectrometry, Mass, Electrospray Ionization; D015032:Zinc / Q000378:metabolism
chemical_list: D002614:Chelating Agents; D010455:Peptides; D011328:Prions; D003300:Copper; D009532:Nickel; D015032:Zinc