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-Structure paper
タイトル | An atomic model for the human septin hexamer by cryo-EM. |
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ジャーナル・号・ページ | J Mol Biol, Vol. 433, Issue 15, Page 167096, Year 2021 |
掲載日 | 2021年7月23日 |
著者 | Deborah C Mendonça / Samuel L Guimarães / Humberto D'Muniz Pereira / Andressa A Pinto / Marcelo A de Farias / Andre S de Godoy / Ana P U Araujo / Marin van Heel / Rodrigo V Portugal / Richard C Garratt / |
PubMed 要旨 | In order to form functional filaments, human septins must assemble into hetero-oligomeric rod-like particles which polymerize end-to-end. The rules governing the assembly of these particles and the ...In order to form functional filaments, human septins must assemble into hetero-oligomeric rod-like particles which polymerize end-to-end. The rules governing the assembly of these particles and the subsequent filaments are incompletely understood. Although crystallographic approaches have been successful in studying the separate components of the system, there has been difficulty in obtaining high resolution structures of the full particle. Here we report a first cryo-EM structure for a hexameric rod composed of human septins 2, 6 and 7 with a global resolution of ~3.6 Å and a local resolution of between ~3.0 Å and ~5.0 Å. By fitting the previously determined high-resolution crystal structures of the component subunits into the cryo-EM map, we are able to provide an essentially complete model for the particle. This exposes SEPT2 NC-interfaces at the termini of the hexamer and leaves internal cavities between the SEPT6-SEPT7 pairs. The floor of the cavity is formed by the two α helices including their polybasic regions. These are locked into place between the two subunits by interactions made with the α and α helices of the neighbouring monomer together with its polyacidic region. The cavity may serve to provide space allowing the subunits to move with respect to one another. The elongated particle shows a tendency to bend at its centre where two copies of SEPT7 form a homodimeric G-interface. Such bending is almost certainly related to the ability of septin filaments to recognize and even induce membrane curvature. |
リンク | J Mol Biol / PubMed:34116125 |
手法 | EM (単粒子) |
解像度 | 3.6 Å |
構造データ | EMDB-23698, PDB-7m6j: |
化合物 | ChemComp-GDP: ChemComp-GTP: ChemComp-MG: |
由来 |
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キーワード | CELL CYCLE / Complex / SPA / Cytoskeleton |