8RTX

Crystal Structure of an Anti-idiotype Fab Fragment

8RTX の概要

• エントリーDOI: 10.2210/pdb8rtx/pdb
• 分子名称: Anti-IC Fab fragment B12 light chain, Anti-IC Fab fragment B12 heavy chain (2 entities in total)
• 機能のキーワード: fab, idiotype, immune system
• 由来する生物種: Mus musculus; 詳細
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 141141.83

構造登録者

Eronen, V.,Parkkinen, T.,Hakulinen, N.,Rouvinen, J. (登録日: 2024-01-29, 公開日: 2024-09-18, 最終更新日: 2024-11-13)

主引用文献

Eronen, V.,Takkinen, K.,Torni, A.,Peng, K.,Janis, J.,Parkkinen, T.,Hakulinen, N.,Rouvinen, J.
Structural insights into ternary immunocomplex formation and cross-reactivity: binding of an anti-immunocomplex FabB12 to Fab220-testosterone complex.
Febs J., 291:4744-4756, 2024

PubMed Abstract: Anti-immunocomplex (Anti-IC) antibodies have been used in developing noncompetitive immunoassays for detecting small molecule analytics (haptens). These antibodies bind specifically to the primary antibody in complex with hapten. Although several anti-IC antibody-based immunoassays have been developed, structural studies of these systems are very limited. In this study, we determined the crystal structures of anti-testosterone Fab220 in complex with testosterone and the corresponding anti-IC antibody FabB12. The structure of the ternary complex of testosterone, Fab220, and FabB12 was predicted using LightDock and AlphaFold. The ternary complex has a large (~ 1100 Å) interface between antibodies. The A-ring of the testosterone bound by Fab220 also participates in the binding of the anti-IC antibody. The structural analysis was complemented by native mass spectrometry. The affinities for testosterone (TES) and three cross-reactive steroids [dihydrotestosterone (DHT), androstenedione (A4), and dehydroepiandrosterone sulfate (DHEA-S)] were measured, and ternary complex formation was studied. The results clearly show the ternary complex formation in the solution. Although DHT showed significant cross-reactivity, A4 and DHEA-S exhibited minor cross-reactivity.

PubMed: 39206623
DOI: 10.1111/febs.17258

実験手法

X-RAY DIFFRACTION (2.7 Å)