Multiple oligomeric states of the Helicobacter pylori vacuolating toxin demonstrated by cryo-electron microscopy

Détails

ID Serval
serval:BIB_2395B944AEDA
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Multiple oligomeric states of the Helicobacter pylori vacuolating toxin demonstrated by cryo-electron microscopy
Périodique
Journal of Molecular Biology
Auteur(s)
Adrian  M., Cover  T. L., Dubochet  J., Heuser  J. E.
ISSN
0022-2836 (Print)
Statut éditorial
Publié
Date de publication
04/2002
Volume
318
Numéro
1
Pages
121-33
Notes
Comparative Study
Journal Article
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S. --- Old month value: Apr 19
Résumé
Helicobacter pylori vacuolating toxin (VacA) is a bacterial protein toxin that forms water-soluble oligomeric complexes, and can somehow insert into lipid bilayers to produce anion-selective channels. In this study, we utilize the novel technique of "cryo-negative staining" to examine the morphology of vitrified VacA complexes. Two basic types of oligomeric structures were observed: (i) relatively thick six or seven-sided astral arrays with near-perfect radial symmetry; and (ii) relatively thin astral arrays of six to nine short "rodlets" that display a distinct handedness or "chirality". Additionally, the new technique provided edge-views of the thicker form of VacA oligomer, which appears to be a thin bilayered disc, indicating that the relatively thick six-sided arrays are actually dodecamers. Also observed occasionally in the present cryo-negatively stained VacA preparations were 2D crystalline arrays that appeared to be comprised of interlocked dodecamers. The structural alterations that VacA oligomers must undergo to form these 2D crystals were analyzed, and intermediates in this transition were identified. Additionally, the oligomeric state of acid-activated VacA bound to membranes was visualized by the traditional technique of "deep-etch" electron microscopy, and was found to resemble most closely the top halves of the dodecamers. These results indicate that VacA is able to undergo major conformational changes, accompanied by major changes in its state of oligomerization, under different natural and experimental conditions.
Mots-clé
Animals Bacterial Proteins/*chemistry Bacterial Toxins/*chemistry/isolation & purification Biopolymers Cryoelectron Microscopy/*methods Erythrocytes/metabolism/ultrastructure Helicobacter pylori/*metabolism Lipid Bilayers Liposomes Models, Molecular Protein Conformation Rabbits Vacuoles/physiology
Pubmed
Web of science
Création de la notice
24/01/2008 11:25
Dernière modification de la notice
03/03/2018 14:55
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