Next Article in Journal
Neutralization of the Principal Toxins from the Venoms of Thai Naja kaouthia and Malaysian Hydrophis schistosus: Insights into Toxin-Specific Neutralization by Two Different Antivenoms
Next Article in Special Issue
EGA Protects Mammalian Cells from Clostridium difficile CDT, Clostridium perfringens Iota Toxin and Clostridium botulinum C2 Toxin
Previous Article in Journal
Rapid Detection of Escherichia coli O157 and Shiga Toxins by Lateral Flow Immunoassays
Previous Article in Special Issue
Clostridium perfringens Enterotoxin: Action, Genetics, and Translational Applications
Article Menu
Issue 4 (April) cover image

Export Article

Open AccessArticle
Toxins 2016, 8(4), 90; doi:10.3390/toxins8040090

The Tip of the Four N-Terminal α-Helices of Clostridium sordellii Lethal Toxin Contains the Interaction Site with Membrane Phosphatidylserine Facilitating Small GTPases Glucosylation

1
Unité des Bactéries anaérobies et Toxines, Institut Pasteur, 75724 Paris cedex15, France
2
Plate-Forme de Biophysique Moléculaires, Institut Pasteur, 75724 Paris cedex15, France
3
Unité de Biochimie des Interactions Macromoléculaires, Institut Pasteur, 75724 Paris cedex15, France
4
Unité de Bioinformatique Structurale, Institut Pasteur, 75724 Paris cedex15, France
*
Author to whom correspondence should be addressed.
Academic Editor: Joachim Orth
Received: 5 February 2016 / Revised: 1 March 2016 / Accepted: 10 March 2016 / Published: 25 March 2016
View Full-Text   |   Download PDF [4390 KB, uploaded 25 March 2016]   |  

Abstract

Clostridium sordellii lethal toxin (TcsL) is a powerful virulence factor responsible for severe toxic shock in man and animals. TcsL belongs to the large clostridial glucosylating toxin (LCGT) family which inactivates small GTPases by glucosylation with uridine-diphosphate (UDP)-glucose as a cofactor. Notably, TcsL modifies Rac and Ras GTPases, leading to drastic alteration of the actin cytoskeleton and cell viability. TcsL enters cells via receptor-mediated endocytosis and delivers the N-terminal glucosylating domain (TcsL-cat) into the cytosol. TcsL-cat was found to preferentially bind to phosphatidylserine (PS)-containing membranes and to increase the glucosylation of Rac anchored to the lipid membrane. We have previously reported that the N-terminal four helical bundle structure (1–93 domain) recognizes a broad range of lipids, but that TcsL-cat specifically binds to PS and phosphatidic acid. Here, we show using mutagenesis that the PS binding site is localized on the tip of the four-helix bundle which is rich in positively-charged amino acids. Residues Y14, V15, F17, and R18 on loop 1, between helices 1 and 2, in coordination with R68 from loop 3, between helices 3 and 4, form a pocket which accommodates L-serine. The functional PS-binding site is required for TcsL-cat binding to the plasma membrane and subsequent cytotoxicity. TcsL-cat binding to PS facilitates a high enzymatic activity towards membrane-anchored Ras by about three orders of magnitude as compared to Ras in solution. The PS-binding site is conserved in LCGTs, which likely retain a common mechanism of binding to the membrane for their full activity towards membrane-bound GTPases. View Full-Text
Keywords: Clostridium sordellii; Clostridium difficile; large clostridial glucosylating toxin; C. sordellii lethal toxin; phosphatidylserine; Ras Clostridium sordellii; Clostridium difficile; large clostridial glucosylating toxin; C. sordellii lethal toxin; phosphatidylserine; Ras
Figures

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Supplementary material

Scifeed alert for new publications

Never miss any articles matching your research from any publisher
  • Get alerts for new papers matching your research
  • Find out the new papers from selected authors
  • Updated daily for 49'000+ journals and 6000+ publishers
  • Define your Scifeed now

SciFeed Share & Cite This Article

MDPI and ACS Style

Varela Chavez, C.; Haustant, G.M.; Baron, B.; England, P.; Chenal, A.; Pauillac, S.; Blondel, A.; Popoff, M.-R. The Tip of the Four N-Terminal α-Helices of Clostridium sordellii Lethal Toxin Contains the Interaction Site with Membrane Phosphatidylserine Facilitating Small GTPases Glucosylation. Toxins 2016, 8, 90.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Toxins EISSN 2072-6651 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top