All-or-none membrane permeabilization by fengycin-type lipopeptides from Bacillus subtilis QST713
2011 (English)In: Biochimica et Biophysica Acta - Biomembranes, ISSN 0005-2736, E-ISSN 1879-2642, Vol. 1808, no 8, 2000-2008 p.Article in journal (Refereed) Published
The fungicidal activity of Bacillus subtilis QST713 has been utilized for the highly effective and environmentally safe protection of crops against a variety of pathogens. It is based mainly on the production of cyclic lipopeptides of the fengycin (FEs), surfactin, and iturin families. The mixed population of native FEs forms micelles which solubilize individual FEs such as agrastatin 1 (AS1) that are otherwise rather insoluble on their own. Fluorescence lifetime-based calcein efflux measurements and cryo transmission electron microscopy show that these FEs show a unique scenario of membrane permeabilization. Poor miscibility of FEs with lipid probably promotes the formation of pores in 10% of the vesicles at onlyï¿œ[approximate]ï¿œ1ï¿œ[mu]M free FE and in 15% of the vesicles at 10ï¿œ[mu]M. We explain why this limited, all-or-none leakage could nevertheless account for the killing of virtually all fungi whereas the same extent of graded vesicle leakage may be biologically irrelevant. Then, crystallization of AS1 and micellization of plipastatins cause a cut-off in leakage at 15% that might regulate the biological activity of FEs, protecting Bacillus and plant membranes. The fact that FE micelles solubilize only about 10ï¿œmol-% fluid lipid resembles the behavior of detergent resistance.
Place, publisher, year, edition, pages
2011. Vol. 1808, no 8, 2000-2008 p.
Antibiotic peptide, Fungicide, Biofilm, Biosurfactant, Time resolved fluorescence spectroscopy, All-or-none leakage
IdentifiersURN: urn:nbn:se:uu:diva-155045DOI: 10.1016/j.bbamem.2011.04.008ISI: 000292350300006PubMedID: 21545788OAI: oai:DiVA.org:uu-155045DiVA: diva2:423478