title: Complement activation by cross-linked truncated and chimeric full-length beta-amyloid.
abstract: The activation of complement by beta-amyloid (A beta) has been implicated in the local inflammatory response in Alzheimer's disease. To assess the structural parameters required for this activation, beta-sheet-containing fibrils of A beta1-28 were induced by low pH and then chemically cross-linked to constrain the beta-sheet conformation. Chimeric A beta peptides with a substituted C-terminal sequence derived from two different transmembrane proteins were also assessed for the ability to form fibrils rich in beta-sheet structure and to activate complement. Both the cross-linked A beta1-28 and the chimeric A beta peptides were strong activators of the classical complement pathway. These results suggest that the C-terminal residues (29-42) of A beta facilitate fibril assembly required for complement activation but do not contain the interaction sites required for complement activation, further supporting the hypothesis that C1q binds to the N-terminal hydrophilic domain of A beta, and that a fibrillar beta-sheet-rich conformation is required for effective binding and activation of C1.
authors.affiliation: Institute for Brain Aging and Dementia, Department of Neurology, University of California Irvine, 92697-4540, USA.
authors.forename: D H
authors.initials: DH
authors.lastname: Cribbs
authors.forename: P
authors.initials: P
authors.lastname: Velazquez
authors.forename: B
authors.initials: B
authors.lastname: Soreghan
authors.forename: C G
authors.initials: CG
authors.lastname: Glabe
authors.forename: A J
authors.initials: AJ
authors.lastname: Tenner
mesh_terms: D000595:Amino Acid Sequence; D016229:Amyloid beta-Peptides / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D001665:Binding Sites; D003167:Complement Activation / Q000187:drug effects*; D015922:Complement C1q / Q000187:drug effects / Q000378:metabolism; D003432:Cross-Linking Reagents; D005022:Ethyldimethylaminopropyl Carbodiimide; D006168:Guinea Pigs; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000494:pharmacology; D017384:Sequence Deletion
chemical_list: D016229:Amyloid beta-Peptides; D003432:Cross-Linking Reagents; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D015922:Complement C1q; D005022:Ethyldimethylaminopropyl Carbodiimide