title: Conformational studies on beta-amyloid protein carboxy-terminal region (residues 34-42): strategic use of amide backbone protection as a structural probe.
abstract: Analogues of beta-amyloid (32-42) peptide, containing N-(2-hydroxy-4-methoxybenzyl) (Hmb) amide backbone substitutions at various positions have been prepared using fluoren-9-ylmethoxycarbonyl (Fmoc)-polyamide based solid phase peptide synthesis. On-line N alpha-Fmoc deprotection monitoring during assembly exhibited hindered release in the native and beta A(34-42, (Hmb)Gly38) analogue syntheses. No such hindrance was observed during the synthesis of beta A(34-42, (Hmb)Gly37) nor beta A(34-42, (Hmb)Val36). However, the latter contained an exceptionally slow coupling reaction. Cleaved peptides were analysed for solubility in a variety of solvents and insoluble pellets tested for congophilic staining. X-ray analysis of Fmoc (and H-) beta A(34-42) and the corresponding (Hmb)Gly38 analogues as dimethylformamide swollen gels gave very similar structures. Secondary structure prediction and model-building of ordered arrays, compatible with our results, suggest that beta A(34-42) forms a beta-hairpin structure, with the reverse turn at Val36-Gly37-Gly38-Val39 both in solution and on the resin during synthesis.
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge, UK.
authors.forename: M
authors.initials: M
authors.lastname: Quibell
authors.forename: T
authors.initials: T
authors.lastname: Johnson
authors.forename: W G
authors.initials: WG
authors.lastname: Turnell
mesh_terms: D000577:Amides; D016229:Amyloid beta-Peptides / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006801:Humans; D008958:Models, Molecular; D011487:Protein Conformation
chemical_list: D000577:Amides; D016229:Amyloid beta-Peptides