Show simple item record

dc.contributor.authorRodnin, Mykola V.
dc.contributor.authorKashipathy, Maithri M.
dc.contributor.authorKyrychenko, Alexander
dc.contributor.authorBattaile, Kevin P.
dc.contributor.authorLovell, Scott
dc.contributor.authorLadokhin, Alexey S.
dc.identifier.citationRodnin, M. V., Kashipathy, M. M., Kyrychenko, A., Battaile, K. P., Lovell, S., & Ladokhin, A. S. (2020). Structure of the Diphtheria Toxin at Acidic pH: Implications for the Conformational Switching of the Translocation Domain. Toxins, 12(11), 704.
dc.descriptionThis article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license.en_US
dc.description.abstractDiphtheria toxin, an exotoxin secreted by Corynebacterium that causes disease in humans by inhibiting protein synthesis, enters the cell via receptor-mediated endocytosis. The subsequent endosomal acidification triggers a series of conformational changes, resulting in the refolding and membrane insertion of the translocation (T-)domain and ultimately leading to the translocation of the catalytic domain into the cytoplasm. Here, we use X-ray crystallography along with circular dichroism and fluorescence spectroscopy to gain insight into the mechanism of the early stages of pH-dependent conformational transition. For the first time, we present the high-resolution structure of the diphtheria toxin at a mildly acidic pH (5–6) and compare it to the structure at neutral pH (7). We demonstrate that neither catalytic nor receptor-binding domains change their structure upon this acidification, while the T-domain undergoes a conformational change that results in the unfolding of the TH2–3 helices. Surprisingly, the TH1 helix maintains its conformation in the crystal of the full-length toxin even at pH 5. This contrasts with the evidence from the new and previously published data, obtained by spectroscopic measurements and molecular dynamics computer simulations, which indicate the refolding of TH1 upon the acidification of the isolated T-domain. The overall results imply that the membrane interactions of the T-domain are critical in ensuring the proper conformational changes required for the preparation of the diphtheria toxin for the cellular entry.en_US
dc.description.sponsorshipNational Institute of General Medical Sciences (P30 GM110761)en_US
dc.description.sponsorshipDepartment of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. DE-AC02-06CH11357en_US
dc.rights© 2020 by the authors. Licensee MDPI, Basel, Switzerland.en_US
dc.subjectDiphtheria toxin structureen_US
dc.subjectX-ray crystallographyen_US
dc.subjectHelix unfoldingen_US
dc.subjectConformational switchingen_US
dc.titleStructure of the Diphtheria Toxin at Acidic pH: Implications for the Conformational Switching of the Translocation Domainen_US
kusw.kuauthorKashipathy, Maithri M.
kusw.kudepartmentProtein Structure Laboratoryen_US
kusw.oaversionScholarly/refereed, publisher versionen_US
kusw.oapolicyThis item meets KU Open Access policy criteria.en_US

Files in this item


This item appears in the following Collection(s)

Show simple item record

© 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Except where otherwise noted, this item's license is described as: © 2020 by the authors. Licensee MDPI, Basel, Switzerland.