title: Role of N- or C-terminal biotinylation in autoantibody recognition of citrullin containing filaggrin epitope peptides in rheumatoid arthritis.
abstract: Here, we report on the synthesis, conformational analysis, and autoantibody binding properties of new sets of rheumatoid arthritis (RA) specific biotin-peptide conjugates derived from filaggrin epitope peptides. The biotin with or without a linker was attached to the Cit or Arg containing epitope core ((311)TXGRS(315)) or epitope region ((306)SHQESTXGXSXGRSGRSGS(324)) peptide (where X = Cit), through an amide bond at the N- or C-terminal of the epitopes. Antibody binding was detected by indirect enzyme-linked immunosorbent assay (ELISA) using sera from RA, Systemic lupus erythematosus (SLE) patients, as well as healthy individuals, and the secondary structure of conjugates was investigated by electronic circular dichroism (ECD). We found that autoantibodies from RA patients recognize specifically both filaggrin epitope region ((306)SHQESTXGXSXGRSGRSGS(324)) and short epitope core ((311)TXGRS(315)) peptides. Our data also indicate that the positioning of the biotin label within a peptide sequence can markedly influence the antibody binding, but the length of the linker incorporated has essentially no effect on the recognition. ECD experiments demonstrate that the Arg/Cit change does not influence the solution conformation of the peptide conjugates. However, the presence and position of the biotin moiety has a pronounced effect on the conformation of the 5-mer epitope core peptides, while it does not alter the secondary structure of the 19-mer epitope region peptides.
authors.affiliation: Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary.
authors.forename: Fruzsina
authors.initials: F
authors.lastname: Babos
authors.forename: Eszter
authors.initials: E
authors.lastname: Szarka
authors.forename: György
authors.initials: G
authors.lastname: Nagy
authors.forename: Zsuzsa
authors.initials: Z
authors.lastname: Majer
authors.forename: Gabriella
authors.initials: G
authors.lastname: Sármay
authors.forename: Anna
authors.initials: A
authors.lastname: Magyar
authors.forename: Ferenc
authors.initials: F
authors.lastname: Hudecz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000595:Amino Acid Sequence; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000276:immunology*; D001323:Autoantibodies / Q000276:immunology*; D019921:Biotinylation; D002956:Citrulline / Q000737:chemistry / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry / Q000276:immunology*; D000091344:Filaggrin Proteins; D006801:Humans; D007381:Intermediate Filament Proteins / Q000737:chemistry / Q000276:immunology*; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000276:immunology; D008875:Middle Aged; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000276:immunology*; D017433:Protein Structure, Secondary
chemical_list: D001323:Autoantibodies; D000939:Epitopes; C000717249:FLG protein, human; D000091344:Filaggrin Proteins; D007381:Intermediate Filament Proteins; D010455:Peptides; D002956:Citrulline