The structure of bacterial toxin CNFY reveals requirements for secretion, host cell recognition and endosomal release

Chaoprasid, P.; Lukat, P.; Mühlen, S.; Schweer, J. N. G.; Heidler, T. V.; Gazdag, E. M.; Stradal, T.; Dersch, P.; Blankenfeldt, W.

doi:10.1101/2020.04.07.029181

bioRxiv · 10.1101/2020.04.07.029181

The structure of bacterial toxin CNFY reveals requirements for secretion, host cell recognition and endosomal release

Chaoprasid, P.·Lukat, P.·Mühlen, S.·Schweer, J. N. G.·Heidler, T. V.·Gazdag, E. M.·Stradal, T.·Dersch, P.·Blankenfeldt, W.

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Abstract

Cytotoxic necrotizing factors (CNFs) are bacterial single-chain exotoxins that modulate cytokinetic/oncogenic and inflammatory processes through activation of host cell Rho GTPases. To achieve this, they are secreted, bind surface receptors to induce endocytosis and translocate a catalytic unit into the cytosol to intoxicate host cells. A three-dimensional structure that provides insight into the underlying mechanisms is still lacking. Here, we determined the crystal structure of full-length Yersinia pseudotuberculosis CNFY. CNFY consists of five domains (D1-D5), and by integrating structural and functional data we demonstrate that D1-3 act as export and translocation module for the catalytic unit (D4-5) or fused {beta}-lactamase reporter proteins. We further found that domain D4, which possesses structural similarity to ADP-ribosyl transferases, but had no equivalent catalytic activity, changed its position to interact extensively with D5 in the crystal structure of the free D4-5 fragment. This liberates D5 from a semi-blocked conformation in full-length CNFY, leading to higher deamidation activity. Finally, sequence comparisons identified the CNF translocation module in many uncharacterized bacterial proteins, suggesting its usability as a universal drug delivery tool.

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Chaoprasid, P., Lukat, P., Mühlen, S., Schweer, J. N. G., Heidler, T. V., Gazdag, E. M., Stradal, T., Dersch, P., Blankenfeldt, W.. 2020-04-08. The structure of bacterial toxin CNFY reveals requirements for secretion, host cell recognition and endosomal release. https://doi.org/10.1101/2020.04.07.029181

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