Change search
ReferencesLink to record
Permanent link

Direct link
Channel-Forming Abilities of Spontaneously Occurring alpha-Toxin Fragments from Staphylococcus aureus
Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
2010 (English)In: Journal of Membrane Biology, ISSN 0022-2631, E-ISSN 1432-1424, Vol. 234, no 3, 171-181 p.Article in journal (Refereed) Published
Abstract [en]

Pore formation by four spontaneously occurring alpha-toxin fragments from Staphylococcus aureus were investigated on liposome and erythrocyte membranes. All the isolated fragments bound to the different types of membranes and formed transmembrane channels in egg-phosphatidyl glycerol vesicles. Fragments of amino acids (aa) 9-293 (32 kD) and aa 13-293 (31 kD) formed heptamers, similar to the intact toxin, while the aa 72-293 (26 kD) fragment formed heptamers, octamers, and nonamers, as judged by gel electrophoresis of the liposomes. All isolated fragments induced release of chloride ions from large unilamellar vesicles. Channel formation was promoted by acidic pH and negatively charged lipid head groups. Also, the fragments' hemolytic activity was strongly decreased under neutral conditions but could be partially restored by acidification of the medium. We paid special attention to the 26-kD fragment, which, despite the loss of about one-fourth of the N-terminal part of alpha-toxin, did form transmembrane channels in liposomes. In light of the available data on channel formation by alpha-toxin, our results suggest that proteolytic degradation might be better tolerated than previously reported. Channel opening could be inhibited and open channels could be closed by zinc in the medium. Channel closure could be reversed by addition of EDTA. In contrast, digestion at the C terminus led to premature oligomerization and resulted in species with strongly diminished activity and dependent on protonation.

Place, publisher, year, edition, pages
2010. Vol. 234, no 3, 171-181 p.
Keyword [en]
alpha-Toxin fragments, Hemolysis, Large unilamellar vesicles, Oligomerization, Channel formation
National Category
Natural Sciences
URN: urn:nbn:se:su:diva-50687DOI: 10.1007/s00232-010-9244-7ISI: 000276511300003OAI: diva2:382268
authorCount :4Available from: 2010-12-30 Created: 2010-12-30 Last updated: 2010-12-30Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Högbom, Martin
By organisation
Department of Biochemistry and Biophysics
In the same journal
Journal of Membrane Biology
Natural Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 13 hits
ReferencesLink to record
Permanent link

Direct link