Abstract
We report the first observation of an efficient, native membrane conjugation mechanism via positively charged, linear oligo-amines. Clustering of membrane fragments relies on electrostatic interactions between the net negative charge of the membranes and the positively charged, water-soluble mediators. This conjugation principle is demonstrated with two different bacterial membranes in which are embedded either the intrinsic membrane protein (MP) bacteriorhodopsin (bR) or the more recently identified xanthorhodopsin (XR). As determined by their characteristic UV-vis absorption spectra and by circular dichroism, the MPs are not significantly perturbed by the oligo-amines carrying from +3 to +6 positive charges. Light microscopy and scanning electron microscope (SEM) imaging provide direct evidence for membrane conjugation. Process efficiency was found to be correlated with the net charge of the oligo-amine used. Membrane conjugation is accomplished within a wide range of pH values (7-2.5); is reversed by NaCl; and does not require the presence of a precipitant (e.g. PEG) nor Ca2+ ions. Some evidence for bilayer fusion is also observed, but only in the presence of the +6 oligo-amine analog.
| Original language | English |
|---|---|
| Article number | 111101 |
| Number of pages | 10 |
| Journal | Colloids And Surfaces B-Biointerfaces |
| Volume | 193 |
| Early online date | 4 May 2020 |
| DOIs | |
| Publication status | Published - Sept 2020 |
Funding
We thank the Kimmelman Center for Biomolecular Structure and Assembly and the Benoziyo Endowment Fund for the Advancement of Science for their generous support to M.S. M.S. holds the Katzir-Makineni Chair in Chemistry. G. P. thanks the research authority of Ariel University for providing the necessary funds for his use of the electron microscope facility.