7S63

Native-form oocyte/egg Alpha-2-Macroglobulin (A2Moo) tetramer

7S63 の概要

• エントリーDOI: 10.2210/pdb7s63/pdb
• EMDBエントリー: 24848
• 分子名称: Alpha 2-Macroglobulin, 2-acetamido-2-deoxy-beta-D-glucopyranose (2 entities in total)
• 機能のキーワード: xenopus egg extract, protease inhibitor, protein binding
• 由来する生物種: Xenopus laevis (African clawed frog)
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 652965.39

構造登録者

Arimura, Y.,Funabiki, H. (登録日: 2021-09-13, 公開日: 2022-01-05, 最終更新日: 2024-11-20)

主引用文献

Arimura, Y.,Funabiki, H.
Structural Mechanics of the Alpha-2-Macroglobulin Transformation.
J.Mol.Biol., 434:167413-167413, 2021

PubMed Abstract: Alpha-2-Macroglobulin (A2M) is the critical pan-protease inhibitor of the innate immune system. When proteases cleave the A2M bait region, global structural transformation of the A2M tetramer is triggered to entrap the protease. The structural basis behind the cleavage-induced transformation and the protease entrapment remains unclear. Here, we report cryo-EM structures of native- and intermediate-forms of the Xenopus laevis egg A2M homolog (A2Moo or ovomacroglobulin) tetramer at 3.7-4.1 Å and 6.4 Å resolution, respectively. In the native A2Moo tetramer, two pairs of dimers arrange into a cross-like configuration with four 60 Å-wide bait-exposing grooves. Each bait in the native form threads into an aperture formed by three macroglobulin domains (MG2, MG3, MG6). The bait is released from the narrowed aperture in the induced protomer of the intermediate form. We propose that the intact bait region works as a "latch-lock" to block futile A2M transformation until its protease-mediated cleavage.

PubMed: 34942166
DOI: 10.1016/j.jmb.2021.167413

実験手法

ELECTRON MICROSCOPY (4.12 Å)