ジャーナル: Nat Commun / 年: 2020 タイトル: Glycan-dependent cell adhesion mechanism of Tc toxins. 著者: Daniel Roderer / Felix Bröcker / Oleg Sitsel / Paulina Kaplonek / Franziska Leidreiter / Peter H Seeberger / Stefan Raunser / 要旨: Toxin complex (Tc) toxins are virulence factors of pathogenic bacteria. Tcs are composed of three subunits: TcA, TcB and TcC. TcA facilitates receptor-toxin interaction and membrane permeation, TcB ...Toxin complex (Tc) toxins are virulence factors of pathogenic bacteria. Tcs are composed of three subunits: TcA, TcB and TcC. TcA facilitates receptor-toxin interaction and membrane permeation, TcB and TcC form a toxin-encapsulating cocoon. While the mechanisms of holotoxin assembly and pore formation have been described, little is known about receptor binding of TcAs. Here, we identify heparins/heparan sulfates and Lewis antigens as receptors for different TcAs from insect and human pathogens. Glycan array screening reveals that all tested TcAs bind negatively charged heparins. Cryo-EM structures of Morganella morganii TcdA4 and Xenorhabdus nematophila XptA1 reveal that heparins/heparan sulfates unexpectedly bind to different regions of the shell domain, including receptor-binding domains. In addition, Photorhabdus luminescens TcdA1 binds to Lewis antigens with micromolar affinity. Here, the glycan interacts with the receptor-binding domain D of the toxin. Our results suggest a glycan dependent association mechanism of Tc toxins on the host cell surface.
A: A component of insecticidal toxin complex (Tc) B: A component of insecticidal toxin complex (Tc) C: A component of insecticidal toxin complex (Tc) D: A component of insecticidal toxin complex (Tc) E: A component of insecticidal toxin complex (Tc)
名称: Xenorhabdus nematophila XptA1 pentamer in complex with porcine mucosa heparin タイプ: COMPLEX / Entity ID: all / 由来: RECOMBINANT
分子量
値: 1.4 MDa / 実験値: NO
由来(天然)
生物種: Xenorhabdus nematophila (バクテリア)
由来(組換発現)
生物種: Escherichia coli (大腸菌)
緩衝液
pH: 7.5
試料
濃度: 0.1 mg/ml / 包埋: NO / シャドウイング: NO / 染色: NO / 凍結: YES 詳細: 0.10 mg/ml XptA1 were pre-applied on the grid for 30s. Subsequently, the grid was manually blotted and 0.30 mg/ml porcine mucosa heparin was applied and incubated for 4 min.
試料支持
グリッドの材料: GOLD / グリッドのタイプ: Quantifoil R2/1
急速凍結
装置: FEI VITROBOT MARK IV / 凍結剤: ETHANE / 湿度: 100 % / 凍結前の試料温度: 285 K