ジャーナル: J Biol Chem / 年: 2015 タイトル: Structural Basis for Antigen Recognition by Transglutaminase 2-specific Autoantibodies in Celiac Disease. 著者: Xi Chen / Kathrin Hnida / Melissa Ann Graewert / Jan Terje Andersen / Rasmus Iversen / Anne Tuukkanen / Dmitri Svergun / Ludvig M Sollid / 要旨: Antibodies to the autoantigen transglutaminase 2 (TG2) are a hallmark of celiac disease. We have studied the interaction between TG2 and an anti-TG2 antibody (679-14-E06) derived from a single gut ...Antibodies to the autoantigen transglutaminase 2 (TG2) are a hallmark of celiac disease. We have studied the interaction between TG2 and an anti-TG2 antibody (679-14-E06) derived from a single gut IgA plasma cell of a celiac disease patient. The antibody recognizes one of four identified epitopes targeted by antibodies of plasma cells of the disease lesion. The binding interface was identified by small angle x-ray scattering, ab initio and rigid body modeling using the known crystal structure of TG2 and the crystal structure of the antibody Fab fragment, which was solved at 2.4 Å resolution. The result was confirmed by testing binding of the antibody to TG2 mutants by ELISA and surface plasmon resonance. TG2 residues Arg-116 and His-134 were identified to be critical for binding of 679-14-E06 as well as other epitope 1 antibodies. In contrast, antibodies directed toward the two other main epitopes (epitopes 2 and 3) were not affected by these mutations. Molecular dynamics simulations suggest interactions of 679-14-E06 with the N-terminal domain of TG2 via the CDR2 and CDR3 loops of the heavy chain and the CDR2 loop of the light chain. In addition there were contacts of the framework 3 region of the heavy chain with the catalytic domain of TG2. The results provide an explanation for the biased usage of certain heavy and light chain gene segments by epitope 1-specific antibodies in celiac disease.
設備名称: PETRA III P12 / 地域: Hamburg / 国: Germany / 線源: X-ray synchrotron / 波長: 0.12 Å / スペクトロメータ・検出器間距離: 3.1 mm
検出器
名称: Pilatus 2M
スキャン
タイトル: anti-TG2 antibody (679 14 E06) / 測定日: 2015年1月17日 / 保管温度: 10 °C / セル温度: 10 °C / 照射時間: 0.05 sec. / フレーム数: 20 / 単位: 1/nm /
Min
Max
Q
0.2017
3.9693
距離分布関数 P(R)
ソフトウェア P(R): GNOM 5.0 / ポイント数: 1044 /
Min
Max
Q
0.0209631
0.295758
P(R) point
1
1044
R
0
81
結果
カーブのタイプ: merged コメント: Structural basis for antigen recognition by transglutaminase 2-specific autoantibodies in celiac disease --- SAXS profile of the autoantibody