9V96
Cryo-EM structure of the inner core of ArlA2 filament of Haloarcula marismortui
Summary for 9V96
| Entry DOI | 10.2210/pdb9v96/pdb |
| EMDB information | 64862 |
| Descriptor | Flagellin, SODIUM ION (2 entities in total) |
| Functional Keywords | archaellum, haloarcheon, protein fibril |
| Biological source | Haloarcula marismortui |
| Total number of polymer chains | 38 |
| Total formula weight | 1801410.41 |
| Authors | Meshcheryakov, V.A.,Hyun, J.,Syutkin, A.S.,Pyatibratov, M.G.,Wolf, M. (deposition date: 2025-05-30, release date: 2026-05-27) |
| Primary citation | Meshcheryakov, V.A.,Hyun, J.,Shibata, S.,Syutkin, A.S.,Pyatibratov, M.G.,Wolf, M. Two types of sheathed archaellum structures from Haloarcula marismortui differ in their outer layer architectures. Nat Commun, 2026 Cited by PubMed Abstract: Many archaea swim by means of rotating helical filaments called archaella. Most archaella are about 10 nm in diameter and comprise multiple copies of the protein archaellin. Here, we describe two archaellum structures formed by the ArlA2 or ArlB archaellins from the haloarchaeon Haloarcula marismortui. We found that both filaments have an additional proteinaceous outer sheath surrounding their inner core, a feature not observed previously in archaea. The outer sheath structures of the two filaments differ fundamentally. The outer domain of ArlB archaellin rotates by 180, forming stable dimers that likely increase the filament rigidity. In contrast, neither rotation nor dimerization of the outer domain was observed in ArlA2 filaments. 3D variability analysis demonstrated that the motions of ArlA2 and ArlB filaments are significantly distinct. Additionally, the ArlB filament displays a larger negatively charged surface area than ArlA2, which may help adaptation to higher salt concentrations. Our structural findings provide insight into how the two filaments can adapt to their different environments. Larger archaellins with additional outer domains can be found in various groups of archaea. We propose that such proteins may allow hosts to modify the properties of their archaella to enhance environmental adaptation. PubMed: 42091601DOI: 10.1038/s41467-026-72670-8 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3.14 Å) |
Structure validation
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