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Evaluation of different approaches used to study membrane permeabilization by actinoporins on model lipid vesicles

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Palacios Ortega, Juan and Rivera de la Torre, Esperanza and Gavilanes, José G. and Slotte, J. Peter and Martínez del Pozo, Álvaro (2020) Evaluation of different approaches used to study membrane permeabilization by actinoporins on model lipid vesicles. BBA. Biomembranes, 1862 (9). ISSN 0005-2736

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Official URL: https://www.sciencedirect.com/science/article/pii/S0005273620301425



Abstract

Release of aqueous contents from model lipid vesicles has been a standard procedure to evaluate pore formation efficiency by actinoporins, such as sticholysin II (StnII), for the last few decades. However, regardless of the probe of choice, the results reported that StnII action was never able to empty the vesicles completely. This was hard to explain if StnII pores were to be stable and always leaky for the probes used. To address this question, we have used a variety of probes, including rhodamine 6G or Tb3+, to test the permeability of StnII’s pores. Our results indicate that calcein was in fact too large to fit through StnII’s pores, and that the standard method in the field is actually reporting StnII-induced transient permeation of the membrane rather than the passage of solutes through the stable assembled pores. In order to evaluate the permeability of these structures, we used a dithionite-based assay, which showed that the final pores were in fact open. Thus, our results indicate that the stable actinoporins’ pores are open in spite of plateaued classic release curves. Besides the proper pore, the first stages of pore formation would inflict serious damage to living cells as well.


Item Type:Article
Uncontrolled Keywords:Pore-forming-proteins, leakage, calcein, rhodamine, terbium, NBD-dithionite
Subjects:Sciences > Chemistry > Molecular biology
Sciences > Chemistry > Biochemistry
ID Code:62190
Deposited On:23 Sep 2020 08:26
Last Modified:23 Sep 2020 08:26

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