title: Prediction of domain organisation and secondary structure of thyroid peroxidase, a human autoantigen involved in destructive thyroiditis.
abstract: Organ specific autoimmune diseases are relatively common immunological disorders in man which include thyroid autoimmune disease, insulin-dependent diabetes mellitus and myasthenia gravis. The target autoantigens in some of these diseases have recently been characterised. In thyroid autoimmune disease this includes the key enzyme, thyroid peroxidase (TPO), which is involved in the generation of thyroid hormone. Structural knowledge about autoantigens such as thyroid peroxidase will allow a greater understanding of the interaction between autoantigens and the aberrant immune response, and facilitate the development of strategies for antigen-specific therapeutic manipulation. We report here a prediction of the secondary structure of thyroid peroxidase, together with the results of circular dichroic spectroscopy of a homologous purified enzyme. A combination of 3 secondary structure prediction programs has been used, following multiple sequence alignment, and TPO has been found to consist mainly of alpha-helical conformation, with little beta-sheet present. This structure prediction, together with knowledge of the exon-intron boundaries allows a model for the domain organisation of the TPO molecule to be proposed.
authors.affiliation: Department of Medicine, King's College School of Medicine, Denmark Hill, London, UK.
authors.forename: J P
authors.initials: JP
authors.lastname: Banga
authors.forename: D
authors.initials: D
authors.lastname: Mahadevan
authors.forename: G J
authors.initials: GJ
authors.lastname: Barton
authors.forename: B J
authors.initials: BJ
authors.lastname: Sutton
authors.forename: J W
authors.initials: JW
authors.lastname: Saldanha
authors.forename: E
authors.initials: E
authors.lastname: Odell
authors.forename: A M
authors.initials: AM
authors.lastname: McGregor
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001324:Autoantigens; D002942:Circular Dichroism; D015935:Complement C4b; D003576:Electron Transport Complex IV; D004815:Epidermal Growth Factor; D006801:Humans; D006860:Hydrogen Bonding; D007453:Iodide Peroxidase; D008969:Molecular Sequence Data; D009195:Peroxidase; D011487:Protein Conformation; D013552:Swine; D013961:Thyroid Gland / Q000201:enzymology*
chemical_list: D001324:Autoantigens; D004815:Epidermal Growth Factor; D015935:Complement C4b; D009195:Peroxidase; D007453:Iodide Peroxidase; D003576:Electron Transport Complex IV