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-Structure paper
Title | Hierarchical organization and assembly of the archaeal cell sheath from an amyloid-like protein. |
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Journal, issue, pages | Nat Commun, Vol. 14, Issue 1, Page 6720, Year 2023 |
Publish date | Oct 23, 2023 |
Authors | Hui Wang / Jiayan Zhang / Daniel Toso / Shiqing Liao / Farzaneh Sedighian / Robert Gunsalus / Z Hong Zhou / |
PubMed Abstract | Certain archaeal cells possess external proteinaceous sheath, whose structure and organization are both unknown. By cellular cryogenic electron tomography (cryoET), here we have determined sheath ...Certain archaeal cells possess external proteinaceous sheath, whose structure and organization are both unknown. By cellular cryogenic electron tomography (cryoET), here we have determined sheath organization of the prototypical archaeon, Methanospirillum hungatei. Fitting of Alphafold-predicted model of the sheath protein (SH) monomer into the 7.9 Å-resolution structure reveals that the sheath cylinder consists of axially stacked β-hoops, each of which is comprised of two to six 400 nm-diameter rings of β-strand arches (β-rings). With both similarities to and differences from amyloid cross-β fibril architecture, each β-ring contains two giant β-sheets contributed by ~ 450 SH monomers that entirely encircle the outer circumference of the cell. Tomograms of immature cells suggest models of sheath biogenesis: oligomerization of SH monomers into β-ring precursors after their membrane-proximal cytoplasmic synthesis, followed by translocation through the unplugged end of a dividing cell, and insertion of nascent β-hoops into the immature sheath cylinder at the junction of two daughter cells. |
External links | Nat Commun / PubMed:37872154 / PubMed Central |
Methods | EM (subtomogram averaging) |
Resolution | 7.92 - 21.8 Å |
Structure data | EMDB-29442: Subtomogram of the 4-beta-ring hoop of M. hungatei sheath structure. EMDB-29443: Subtomogram average of 3-beta-ring hoop structure of M. hungatei sheath EMDB-29448: Subtomogram average of 5-beta-ring hoop structure of M. hungatei sheath |
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