Monovalent ions and water dipoles in contact with dipolar zwitterionic lipid headgroups-theory and MD simulations

Velikonja, Aljaž (author), Perutková, Šárka (author), Gongadze, Ekaterina (author), Kramar, Peter (author), Polak, Andraž (author), Maček Lebar, Alenka (author), Iglič, Aleš (author)

The lipid bilayer is a basic building block of biological membranes and can be pictured as a barrier separating two compartments filled with electrolyte solution. Artificial planar lipid bilayers are therefore commonly used as model systems to study the physical and electrical properties of the cell membranes in contact with electrolyte solution. Among them the glycerol-based polar phospholipids which have dipolar, but electrically neutral head groups, are most frequently used in formation of artificial lipid bilayers. In this work the electrical properties of the lipid layer composed of zwitterionic lipids with non-zero dipole moments are studied theoretically. In the model, the zwitterionic lipid bilayer is assumed to be in contact with aqueous solution of monovalent salt ions. The orientational ordering of water, resulting in spatial variation of permittivity, is explicitly taken into account. It is shown that due to saturation effect in orientational ordering of water dipoles the relative permittivity in the zwitterionic headgroup region is decreased, while the corresponding electric potential becomes strongly negative. Some of the predictions of the presented mean-field theoretical consideration are critically evaluated using the results of molecular dynamics (MD) simulation.

• Language: English
• Keywords: ions, dipoles, lipids, dipolar zwitterionic headgroups, relative permittivity, orientational ordering, water molecules, planar lipid bilayers
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FE - Faculty of Electrical Engineering; MF - Faculty of Medicine
• Publication status: Published
• Publication version: Version of Record
• Year: 2013
• Number of pages: Str. 2846-2861
• Numbering: Vol. 14, iss. 2
• PID: 20.500.12556/RUL-129502
• UDC: 577.115
• ISSN on article: 1422-0067
• DOI: 10.3390/ijms14022846
• COBISS.SI-ID: 9628500
• Publication date in RUL: 02.09.2021

Record is a part of a journal

• Title: International journal of molecular sciences
• Shortened title: Int. j. mol. sci.
• Publisher: MDPI
• ISSN: 1422-0067
• COBISS.SI-ID: 2779162

Licences

• License: CC BY 3.0, Creative Commons Attribution 3.0 Unported
• Link: https://creativecommons.org/licenses/by/3.0/deed.en
• Description: You are free to reproduce and redistribute the material in any medium or format. You are free to remix, transform, and build upon the material for any purpose, even commercially. You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.
• Licensing start date: 01.02.2013

Secondary language

• Language: Slovenian
• Keywords: ioni, dipoli, lipidi