8UEE

Atomic structure of Salmonella SipA/F-actin complex by cryo-EM

8UEE の概要

• エントリーDOI: 10.2210/pdb8uee/pdb
• EMDBエントリー: 42161
• 分子名称: Actin, alpha skeletal muscle, Cell invasion protein SipA, ADENOSINE-5'-DIPHOSPHATE, ... (6 entities in total)
• 機能のキーワード: actin, salmonella, type iii secretion system, sipa, cell invasion
• 由来する生物種: Salmonella enterica subsp. enterica serovar Typhimurium str. LT2; 詳細
• タンパク質・核酸の鎖数: 11
• 化学式量合計: 410610.20

構造登録者

Niedzialkowska, E.,Runyan, L.,Kudryashova, E.,Kudryashov, D.S.,Egelman, E.H. (登録日: 2023-10-01, 公開日: 2023-12-27, 最終更新日: 2024-07-10)

主引用文献

Niedzialkowska, E.,Runyan, L.A.,Kudryashova, E.,Egelman, E.H.,Kudryashov, D.S.
Stabilization of F-actin by Salmonella effector SipA resembles the structural effects of inorganic phosphate and phalloidin.
Structure, 32:725-738.e8, 2024

PubMed Abstract: Entry of Salmonella into host enterocytes relies on its pathogenicity island 1 effector SipA. We found that SipA binds to F-actin in a 1:2 stoichiometry with sub-nanomolar affinity. A cryo-EM reconstruction revealed that SipA's globular core binds at the groove between actin strands, whereas the extended C-terminal arm penetrates deeply into the inter-strand space, stabilizing F-actin from within. The unusually strong binding of SipA is achieved by a combination of fast association via the core and very slow dissociation dictated by the arm. Similar to P, BeF, and phalloidin, SipA potently inhibited actin depolymerization by actin depolymerizing factor (ADF)/cofilin, which correlated with increased filament stiffness, supporting the hypothesis that F-actin's mechanical properties contribute to the recognition of its nucleotide state by protein partners. The remarkably strong binding to F-actin maximizes the toxin's effects at the injection site while minimizing global influence on the cytoskeleton and preventing pathogen detection by the host cell.

PubMed: 38518780
DOI: 10.1016/j.str.2024.02.022

実験手法

ELECTRON MICROSCOPY (3.2 Å)