title: Structural changes of region 1-16 of the Alzheimer disease amyloid beta-peptide upon zinc binding and in vitro aging.
abstract: Amyloid deposits within the cerebral tissue constitute a characteristic lesion associated with Alzheimer disease. They mainly consist of the amyloid peptide Abeta and display an abnormal content in Zn(2+) ions, together with many truncated, isomerized, and racemized forms of Abeta. The region 1-16 of Abeta can be considered the minimal zinc-binding domain and contains two aspartates subject to protein aging. The influence of zinc binding and protein aging related modifications on the conformation of this region of Abeta is of importance given the potentiality of this domain to constitute a therapeutic target, especially for immunization approaches. In this study, we determined from NMR data the solution structure of the Abeta-(1-16)-Zn(2+) complex in aqueous solution at pH 6.5. The residues His(6), His(13), and His(14) and the Glu(11) carboxylate were identified as ligands that tetrahedrally coordinate the Zn(II) cation. In vitro aging experiments on Abeta-(1-16) led to the formation of truncated and isomerized species. The major isomer generated, Abeta-(1-16)-l-iso-Asp(7), displayed a local conformational change in the His(6)-Ser(8) region but kept a zinc binding propensity via a coordination mode involving l-iso-Asp(7). These results are discussed here with regard to Abeta fibrillogenesis and the potentiality of the region 1-16 of Abeta to be used as a therapeutic target.
authors.affiliation: Laboratoire de Chimie et Biochimie des Substances Naturelles, UMR 5154 CNRS-MNHN, Département Régulations, Développement et Diversité Moléculaire, Muséum National d'Histoire Naturelle, 63 Rue Buffon, 75005 Paris, France.
authors.forename: Séverine
authors.initials: S
authors.lastname: Zirah
authors.forename: Sergey A
authors.initials: SA
authors.lastname: Kozin
authors.forename: Alexey K
authors.initials: AK
authors.lastname: Mazur
authors.forename: Alain
authors.initials: A
authors.lastname: Blond
authors.forename: Michel
authors.initials: M
authors.lastname: Cheminant
authors.forename: Isabelle
authors.initials: I
authors.lastname: Ségalas-Milazzo
authors.forename: Pascale
authors.initials: P
authors.lastname: Debey
authors.forename: Sylvie
authors.initials: S
authors.lastname: Rebuffat
mesh_terms: D000375:Aging; D000544:Alzheimer Disease / Q000378:metabolism*; D000595:Amino Acid Sequence; D016229:Amyloid beta-Peptides / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007477:Ions / Q000737:chemistry; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013696:Temperature; D015032:Zinc / Q000737:chemistry*
chemical_list: D016229:Amyloid beta-Peptides; D007477:Ions; D008024:Ligands; D010446:Peptide Fragments; D010455:Peptides; C433241:amyloid beta-protein (1-16); D015032:Zinc