title: Autoantigenicity of human C1q is associated with increased hydrophobicity due to conformational transitions in the globular heads.
abstract: We analyzed the structural features of C1q that underlie its autoantigenicity by means of a model system using the amphiphilic polyzwitterion (PZ), poly(ethylene oxide-b-N,N-dimethyl(methacryloyloxyethyl) ammonium propanesulfonate) in the process of C1q immobilization. The source of anti-C1q autoantibodies was human sera from patients with Lupus Nephritis (LN). Both analyzed concentrations of PZ, 25 mM and 50 mM, were found to be applicable for inducing conformational transitions which resulted in increased recognition of C1q and the globular domain of its B polypeptide chain, designated ghB, by the LN autoantibodies. The registered conformational transitions displayed a hydrophobic enhancement of the protein microenvironment due to the presence of hydrophobic binding sites in ghB which consequently affected the autoantigenicity of the whole C1q molecule.
authors: Sofia University, Faculty of Biology, Dept. of Biochemistry, 8 D. Tsankov St., 1164 Sofia, Bulgaria. itsacheva@biofac.uni-sofia.bg.
authors: Vishnya
authors: V
authors: Stoyanova
authors: Vanya
authors: V
authors: Bogoeva
authors: Lidiya
authors: L
authors: Petrova
authors: Magdalena
authors: M
authors: Tchorbadjieva
authors: Svetla
authors: S
authors: Petrova
authors: Ventsislava
authors: V
authors: Georgieva
authors: George
authors: G
authors: Georgiev
authors: Boriana
authors: B
authors: Deliyska
authors: Vasil
authors: V
authors: Vasilev
authors: Ivanka
authors: I
authors: Tsacheva
mesh_terms: D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D001324:Autoantigens / Q000737:chemistry* / Q000276:immunology*; D015922:Complement C1q / Q000737:chemistry* / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D008181:Lupus Nephritis / Q000276:immunology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000276:immunology; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs / Q000276:immunology*; D021122:Protein Subunits / Q000737:chemistry; D013329:Structure-Activity Relationship; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D007074:Immunoglobulin G; D021122:Protein Subunits; D015922:Complement C1q