PH dependence of listeriolysin O aggregation and pore-forming ability
Listeriolysin O (LLO) is the major factor implicated in the escape of Listeria monocytogenes from the phagolysosome. It is the only representative of cholesterol-dependent cytolysins that exhibits pH-dependent activity. Despite intense studies of LLO pH-dependence, this feature of the toxin still re...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Journal article |
| Language: | English |
| Published: |
2012
|
| _version_ | 1797053219335045120 |
|---|---|
| author | Bavdek, A Kostanjšek, R Antonini, V Lakey, J Dalla Serra, M Gilbert, R Anderluh, G |
| author_facet | Bavdek, A Kostanjšek, R Antonini, V Lakey, J Dalla Serra, M Gilbert, R Anderluh, G |
| author_sort | Bavdek, A |
| collection | OXFORD |
| description | Listeriolysin O (LLO) is the major factor implicated in the escape of Listeria monocytogenes from the phagolysosome. It is the only representative of cholesterol-dependent cytolysins that exhibits pH-dependent activity. Despite intense studies of LLO pH-dependence, this feature of the toxin still remains incompletely explained. Here we used fluorescence and CD spectroscopy to show that the structure of LLO is not detectably affected by pH at room temperature. We observed slightly altered haemolytic and permeabilizing activities at different pH values, which we relate to reduced binding of LLO to the lipid membranes. However, alkaline pH and elevated temperatures caused rapid denaturation of LLO. Aggregates of the toxin were able to bind Congo red and Thioflavin T dyes and were visible under transmission electron microscopy as large, amorphous, micrometer-sized assemblies. The aggregates had the biophysical properties of amyloid. Analytical ultracentrifugation indicated dimerization of the protein in acidic conditions, which protects the protein against premature denaturation in the phagolysosome, where toxin activity takes place. We therefore suggest that LLO spontaneously aggregates at the neutral pH found in the host cell cytosol and that this is a major mechanism of LLO inactivation. © 2011 FEBS. |
| first_indexed | 2024-03-06T18:40:53Z |
| format | Journal article |
| id | oxford-uuid:0cd198c1-1692-4a56-85cc-7977af12be8f |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T18:40:53Z |
| publishDate | 2012 |
| record_format | dspace |
| spelling | oxford-uuid:0cd198c1-1692-4a56-85cc-7977af12be8f2022-03-26T09:37:09ZPH dependence of listeriolysin O aggregation and pore-forming abilityJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:0cd198c1-1692-4a56-85cc-7977af12be8fEnglishSymplectic Elements at Oxford2012Bavdek, AKostanjšek, RAntonini, VLakey, JDalla Serra, MGilbert, RAnderluh, GListeriolysin O (LLO) is the major factor implicated in the escape of Listeria monocytogenes from the phagolysosome. It is the only representative of cholesterol-dependent cytolysins that exhibits pH-dependent activity. Despite intense studies of LLO pH-dependence, this feature of the toxin still remains incompletely explained. Here we used fluorescence and CD spectroscopy to show that the structure of LLO is not detectably affected by pH at room temperature. We observed slightly altered haemolytic and permeabilizing activities at different pH values, which we relate to reduced binding of LLO to the lipid membranes. However, alkaline pH and elevated temperatures caused rapid denaturation of LLO. Aggregates of the toxin were able to bind Congo red and Thioflavin T dyes and were visible under transmission electron microscopy as large, amorphous, micrometer-sized assemblies. The aggregates had the biophysical properties of amyloid. Analytical ultracentrifugation indicated dimerization of the protein in acidic conditions, which protects the protein against premature denaturation in the phagolysosome, where toxin activity takes place. We therefore suggest that LLO spontaneously aggregates at the neutral pH found in the host cell cytosol and that this is a major mechanism of LLO inactivation. © 2011 FEBS. |
| spellingShingle | Bavdek, A Kostanjšek, R Antonini, V Lakey, J Dalla Serra, M Gilbert, R Anderluh, G PH dependence of listeriolysin O aggregation and pore-forming ability |
| title | PH dependence of listeriolysin O aggregation and pore-forming ability |
| title_full | PH dependence of listeriolysin O aggregation and pore-forming ability |
| title_fullStr | PH dependence of listeriolysin O aggregation and pore-forming ability |
| title_full_unstemmed | PH dependence of listeriolysin O aggregation and pore-forming ability |
| title_short | PH dependence of listeriolysin O aggregation and pore-forming ability |
| title_sort | ph dependence of listeriolysin o aggregation and pore forming ability |
| work_keys_str_mv | AT bavdeka phdependenceoflisteriolysinoaggregationandporeformingability AT kostanjsekr phdependenceoflisteriolysinoaggregationandporeformingability AT antoniniv phdependenceoflisteriolysinoaggregationandporeformingability AT lakeyj phdependenceoflisteriolysinoaggregationandporeformingability AT dallaserram phdependenceoflisteriolysinoaggregationandporeformingability AT gilbertr phdependenceoflisteriolysinoaggregationandporeformingability AT anderluhg phdependenceoflisteriolysinoaggregationandporeformingability |