7S64
Intermediate-form oocyte/egg Alpha-2-Macroglobulin (A2Moo) tetramer
This is a non-PDB format compatible entry.
Summary for 7S64
| Entry DOI | 10.2210/pdb7s64/pdb |
| EMDB information | 24849 |
| Descriptor | Alpha 2-macroglobulin (1 entity in total) |
| Functional Keywords | xenopus egg extract, protease inhibitor, protein binding |
| Biological source | Xenopus laevis (African clawed frog) |
| Total number of polymer chains | 4 |
| Total formula weight | 637923.25 |
| Authors | Arimura, Y.,Funabiki, H. (deposition date: 2021-09-13, release date: 2022-01-05, Last modification date: 2024-11-13) |
| Primary citation | Arimura, Y.,Funabiki, H. Structural Mechanics of the Alpha-2-Macroglobulin Transformation. J.Mol.Biol., 434:167413-167413, 2021 Cited by 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: 34942166DOI: 10.1016/j.jmb.2021.167413 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (6.43 Å) |
Structure validation
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