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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| Format: | Article |
| Language: | English |
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MDPI AG
2023-07-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/24/14/11473 |
| _version_ | 1797589060947017728 |
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| author | Marco Colombini Patrick Liu Chase Dee |
| author_facet | Marco Colombini Patrick Liu Chase Dee |
| author_sort | Marco Colombini |
| collection | DOAJ |
| 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. |
| first_indexed | 2024-03-11T01:00:59Z |
| format | Article |
| id | doaj.art-befa89ddb8b64aaaa808787f089f4b31 |
| institution | Directory Open Access Journal |
| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-11T01:00:59Z |
| publishDate | 2023-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Molecular Sciences |
| spelling | doaj.art-befa89ddb8b64aaaa808787f089f4b312023-11-18T19:40:00ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672023-07-0124141147310.3390/ijms241411473Triplin: Mechanistic Basis for Voltage GatingMarco Colombini0Patrick Liu1Chase Dee2Department of Biology, University of Maryland, College Park, MD 20842, USADepartment of Biology, University of Maryland, College Park, MD 20842, USADepartment of Biology, University of Maryland, College Park, MD 20842, USAThe 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.https://www.mdpi.com/1422-0067/24/14/11473voltage dependencevoltage sensorporinprokaryotekineticspolyarginine |
| spellingShingle | Marco Colombini Patrick Liu Chase Dee Triplin: Mechanistic Basis for Voltage Gating International Journal of Molecular Sciences voltage dependence voltage sensor porin prokaryote kinetics polyarginine |
| 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 | voltage dependence voltage sensor porin prokaryote kinetics polyarginine |
| url | https://www.mdpi.com/1422-0067/24/14/11473 |
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