6YEW

Morganella morganii TcdA4 in complex with porcine mucosa heparin

Summary for 6YEW

• Entry DOI: 10.2210/pdb6yew/pdb
• Related: 6RW9
• EMDB information: 10796
• Descriptor: Insecticidal toxin protein (1 entity in total)
• Functional Keywords: toxin, complex, glycan
• Biological source: Morganella morganii
• Total number of polymer chains: 5
• Total formula weight: 1378291.56

Authors

Roderer, D.,Broecker, F.,Sitsel, O.,Kaplonek, P.,Leidreiter, F.,Seeberger, P.H.,Raunser, S. (deposition date: 2020-03-25, release date: 2020-07-08, Last modification date: 2024-05-22)

Primary citation

Roderer, D.,Brocker, F.,Sitsel, O.,Kaplonek, P.,Leidreiter, F.,Seeberger, P.H.,Raunser, S.
Glycan-dependent cell adhesion mechanism of Tc toxins.
Nat Commun, 11:2694-2694, 2020

PubMed Abstract: 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.

PubMed: 32483155
DOI: 10.1038/s41467-020-16536-7

Experimental method

ELECTRON MICROSCOPY (3.2 Å)