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-Structure paper
Title | Cryo-EM structures reveal translocational unfolding in the clostridial binary iota toxin complex. |
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Journal, issue, pages | Nat Struct Mol Biol, Vol. 27, Issue 3, Page 288-296, Year 2020 |
Publish date | Mar 2, 2020 |
Authors | Tomohito Yamada / Toru Yoshida / Akihiro Kawamoto / Kaoru Mitsuoka / Kenji Iwasaki / Hideaki Tsuge / |
PubMed Abstract | The iota toxin produced by Clostridium perfringens type E is a binary toxin comprising two independent polypeptides: Ia, an ADP-ribosyltransferase, and Ib, which is involved in cell binding and ...The iota toxin produced by Clostridium perfringens type E is a binary toxin comprising two independent polypeptides: Ia, an ADP-ribosyltransferase, and Ib, which is involved in cell binding and translocation of Ia across the cell membrane. Here we report cryo-EM structures of the translocation channel Ib-pore and its complex with Ia. The high-resolution Ib-pore structure demonstrates a similar structural framework to that of the catalytic ϕ-clamp of the anthrax protective antigen pore. However, the Ia-bound Ib-pore structure shows a unique binding mode of Ia: one Ia binds to the Ib-pore, and the Ia amino-terminal domain forms multiple weak interactions with two additional Ib-pore constriction sites. Furthermore, Ib-binding induces tilting and partial unfolding of the Ia N-terminal α-helix, permitting its extension to the ϕ-clamp gate. This new mechanism of N-terminal unfolding is crucial for protein translocation. |
External links | Nat Struct Mol Biol / PubMed:32123390 |
Methods | EM (single particle) |
Resolution | 2.8 - 2.9 Å |
Structure data | EMDB-0713, PDB-6klo: |
Chemicals | ChemComp-CA: |
Source |
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Keywords | TOXIN / Bacterial binary toxin / Protein translocation channel / ADP-ribosylation |