High efficiency liposome fusion induced by reducing undesired membrane peptides interaction

Tingting Zheng,Huanhuan Feng,Yun Chen,Yu Shi

doi:10.1515/chem-2019-0004

Abstract

AbstractA full membrane fusion model which attains both complete lipid mixing and content mixing liposomal membranes mediated by coiled-coil forming lipopeptidesLPK[L-PEG12-(KIAALKE)3] andLPE[L-PEG12-(EIAALEK)3] is presented. The electrostatic effects of lipid anchored peptides on fusion efficiency was investigated. For this, the original amino acid sequence of the membrane boundLPKwas varied at its ‘f’-position of the helical structure, i.e. via mutating the anionic glutamate residues by either neutral serines or cationic lysines. Both CD and fluorescence measurements showed that replacing the negatively charged glutamate did not significantly alter the peptide ability to form a coiled coil, but lipid mixing and content mixing assays showed more efficient liposome-liposome fusion resulting in almost quantitative content mixing for the lysine mutated analogue (LPKK) in conjunction withLPE. A mechanism is proposed for a fusion model triggered by membrane destabilizing effects mediated by the membrane destabilizing activety ofLPKin cooperation with the electrostatic activity ofLPE. This new insight may enlightens the further development of a promising nano carrier tool for biomedical applications.

Highlights

A full membrane fusion model which attains both complete lipid mixing and content mixing liposomal membranes mediated by coiled-coil forming lipopeptides LPK [L-PEG12-(KIAALKE)3] and LPE [L-PEG12-(EIAALEK)3] is presented
To investigate whether electrostatic interactions have an effect on the K- and E-peptide mediated membrane fusion and to test the postulated role of the negatively charged glutamates at position ‘f’, two new sequences were synthesized with either the non-charged serine (S) or the positive charged lysine on position ‘f’, denoted K with neutral serines (KS) and KK, respectively
In this study, the N-acetylated peptides, shown in Table 1 were studied by Circular Dichroism (CD) and fluorescence spectroscopy. [7,15,18,31,36]

Summary

Introduction

Abstract: A full membrane fusion model which attains both complete lipid mixing and content mixing liposomal membranes mediated by coiled-coil forming lipopeptides LPK [L-PEG12-(KIAALKE)3] and LPE [L-PEG12-(EIAALEK)3] is presented. The original amino acid sequence of the membrane bound LPK was varied at its ‘f’-position of the helical structure, i.e. via mutating the anionic glutamate residues by either neutral serines or cationic lysines. Both CD and fluorescence measurements showed that replacing the negatively charged glutamate did not significantly alter the peptide ability to form a coiled coil, but lipid mixing and content mixing assays showed more efficient liposome-liposome fusion resulting in almost quantitative content mixing for the lysine mutated analogue (LPKK) in conjunction with LPE. This new insight may enlightens the further development of a promising nano carrier tool for biomedical applications

Methods

Results

Discussion

Conclusion