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Triplin: Mechanistic Basis for Voltage Gating

The outer membrane of Gram-negative bacteria contains a variety of pore-forming structures collectively referred to as porins. Some of these are voltage dependent, but weakly so, closing at high voltages. Triplin, a novel bacterial pore-former, is a three-pore structure, highly voltage dependent, wi...

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Detalles Bibliográficos
Autores principales: Colombini, Marco, Liu, Patrick, Dee, Chase
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10380799/
https://www.ncbi.nlm.nih.gov/pubmed/37511231
http://dx.doi.org/10.3390/ijms241411473
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author Colombini, Marco
Liu, Patrick
Dee, Chase
author_facet Colombini, Marco
Liu, Patrick
Dee, Chase
author_sort Colombini, Marco
collection PubMed
description The outer membrane of Gram-negative bacteria contains a variety of pore-forming structures collectively referred to as porins. Some of these are voltage dependent, but weakly so, closing at high voltages. Triplin, a novel bacterial pore-former, is a three-pore structure, highly voltage dependent, with a complex gating process. The three pores close sequentially: pore 1 at positive potentials, 2 at negative and 3 at positive. A positive domain containing 14 positive charges (the voltage sensor) translocates through the membrane during the closing process, and the translocation is proposed to take place by the domain entering the pore and thus blocking it, resulting in the closed conformation. This mechanism of pore closure is supported by kinetic measurements that show that in the closing process the voltage sensor travels through most of the transmembrane voltage before reaching the energy barrier. Voltage-dependent blockage of the pores by polyarginine, but not by a 500-fold higher concentrations of polylysine, is consistent with the model of pore closure, with the sensor consisting mainly of arginine residues, and with the presence, in each pore, of a complementary surface that serves as a binding site for the sensor.
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spelling pubmed-103807992023-07-29 Triplin: Mechanistic Basis for Voltage Gating Colombini, Marco Liu, Patrick Dee, Chase Int J Mol Sci Article The outer membrane of Gram-negative bacteria contains a variety of pore-forming structures collectively referred to as porins. Some of these are voltage dependent, but weakly so, closing at high voltages. Triplin, a novel bacterial pore-former, is a three-pore structure, highly voltage dependent, with a complex gating process. The three pores close sequentially: pore 1 at positive potentials, 2 at negative and 3 at positive. A positive domain containing 14 positive charges (the voltage sensor) translocates through the membrane during the closing process, and the translocation is proposed to take place by the domain entering the pore and thus blocking it, resulting in the closed conformation. This mechanism of pore closure is supported by kinetic measurements that show that in the closing process the voltage sensor travels through most of the transmembrane voltage before reaching the energy barrier. Voltage-dependent blockage of the pores by polyarginine, but not by a 500-fold higher concentrations of polylysine, is consistent with the model of pore closure, with the sensor consisting mainly of arginine residues, and with the presence, in each pore, of a complementary surface that serves as a binding site for the sensor. MDPI 2023-07-14 /pmc/articles/PMC10380799/ /pubmed/37511231 http://dx.doi.org/10.3390/ijms241411473 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Colombini, Marco
Liu, Patrick
Dee, Chase
Triplin: Mechanistic Basis for Voltage Gating
title Triplin: Mechanistic Basis for Voltage Gating
title_full Triplin: Mechanistic Basis for Voltage Gating
title_fullStr Triplin: Mechanistic Basis for Voltage Gating
title_full_unstemmed Triplin: Mechanistic Basis for Voltage Gating
title_short Triplin: Mechanistic Basis for Voltage Gating
title_sort triplin: mechanistic basis for voltage gating
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10380799/
https://www.ncbi.nlm.nih.gov/pubmed/37511231
http://dx.doi.org/10.3390/ijms241411473
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