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Guanidinium Pairing Facilitates Membrane Translocation

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Original languageEnglish
Pages (from-to)143-153
Number of pages11
JournalJournal of Physical Chemistry Part B
Issue number1
Publication statusPublished - 14 Jan 2016
Publication typeA1 Journal article-refereed


Ab initio free energy calculations of guanidinium pairing in aqueous solution confirm the counterintuitive conjecture that the like-charge ion pair is thermodynamically stable. Transferring the guanidinium pair to the inside of a POPC lipid bilayer, like-charge ion pairing is found to occur also inside the membrane defect. It is found to contribute to the nonadditivity of ion transfer, thereby facilitating the presence of ions inside the bilayer. The effect is quantified by free energy decomposition and comparison with ammonium ions, which do not form a stable pair. The presence of two charges inside the center of the bilayer leads to the formation of a pore. Potential consequences for cell penetrating peptides and ion conduction are drawn.

Publication forum classification

Field of science, Statistics Finland