The cytotoxic domain of colicin e9 is a channel-forming endonuclease

ABSTRACT Bacterial toxins commonly translocate cytotoxic enzymes into cells using channel-forming subunits or domains as conduits. Here we demonstrate that the small cytotoxic endonuclease

domain from the bacterial toxin colicin E9 (E9 DNase) shows nonvoltage-gated, channel-forming activity in planar lipid bilayers that is linked to toxin translocation into cells. A disulfide

bond engineered into the DNase abolished channel activity and colicin toxicity but left endonuclease activity unaffected; NMR experiments suggest decreased conformational flexibility as the

likely reason for these alterations. Concomitant with the reduction of the disulfide bond is the restoration of conformational flexibility, DNase channel activity and colicin toxicity. Our

data suggest that endonuclease domains of colicins may mediate their own translocation across the bacterial inner membrane through an intrinsic channel activity that is dependent on

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CHOLERA TOXIN Article Open access 07 January 2022 TOXIN IMPORT THROUGH THE ANTIBIOTIC EFFLUX CHANNEL TOLC Article Open access 30 July 2021 REFERENCES * Johnson, A.E. & van Waes, M.A. The

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the DNase domain of colicin E9. _J. Biomol. NMR_ 12, 567–568 (1998). Article  CAS  Google Scholar  Download references ACKNOWLEDGEMENTS We thank A. Reilly, C. Moore and N. Cull for expert

technical assistance and A. Leech for help with the acquisition of all mass spectrometry data. We also thank the referees of this paper for their helpful comments. This work was supported by

The Biotechnology and Biological Sciences Research Council. A.H.K. was supported by a Wellcome Trust Prize Studentship. AUTHOR INFORMATION Author notes * Christelle Lemaître Present

address: Laboratoire de Spectrométrie de Masse Bioorganique, Université Louis Pasteur, UMR/ULP CNRS 7509, ECPM 25 rue Becquerel, F-67087, Cedex 2, France * Hamid Mobasheri Present address:

Laboratory of Membrane Biophysics, Institute of Biochemistry and Biophysics, University of Tehran, PO Box 13145-1384, IR, Iran * Khédidja Mosbahi and Christelle Lemaître: These authors

contributed equally to this work. AUTHORS AND AFFILIATIONS * School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK Khédidja Mosbahi, Christelle Lemaître, Anthony H.

Keeble, Hamid Mobasheri, Edward J.A. Lea & Colin Kleanthous * School of Chemical Sciences, University of East Anglia, Norwich, NR4 7TJ, UK Bertrand Morel & Geoffrey R. Moore *

Division of Microbiology and Infectious Diseases, University Hospital, Queen's Medical Centre, University of Nottingham, Nottingham, NG7 2UH, UK Richard James Authors * Khédidja Mosbahi

View author publications You can also search for this author inPubMed Google Scholar * Christelle Lemaître View author publications You can also search for this author inPubMed Google

Scholar * Anthony H. Keeble View author publications You can also search for this author inPubMed Google Scholar * Hamid Mobasheri View author publications You can also search for this

author inPubMed Google Scholar * Bertrand Morel View author publications You can also search for this author inPubMed Google Scholar * Richard James View author publications You can also

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AUTHOR Correspondence to Colin Kleanthous. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing financial interests. RIGHTS AND PERMISSIONS Reprints and permissions

ABOUT THIS ARTICLE CITE THIS ARTICLE Mosbahi, K., Lemaître, C., Keeble, A. _et al._ The cytotoxic domain of colicin E9 is a channel-forming endonuclease. _Nat Struct Mol Biol_ 9, 476–484

(2002). https://doi.org/10.1038/nsb797 Download citation * Received: 18 December 2001 * Accepted: 18 March 2002 * Published: 20 May 2002 * Issue Date: 01 June 2002 * DOI:

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