Work

Solubilisation of model membrane by DDAO surfactant – partitioning, permeabilisation and liposome-micelle transition

Year: 2020

Type: article

Abstract: Solubilisation of model membranes of dioleoylphosphatidylcholine (DOPC) and DOPCcholesterol (CHOL) induced by surfactant N,N-dimethyl-1-dodecanamine-N-oxide (DDAO) was studied. At the maintained pH ~ 7.5, the DDAO molecules are in their neutral state with respect to the pK ~ 5. Pore formation in lipid bilayer was studied by fluorescence probe leakage method. The changes in the size of lipid aggregates upon increasing DDAO concentration were followed turbidimetrically. Effective ratio Re at different steps of the solubilisation process was determined. The molar partition coefficient of DDAO in case of the DOPC membrane is Kp = 2262 ± 379, for DOPC-CHOL membrane Kp = 2092 ± 594. Within the experimental error, the partition coefficient, as well as effective ratios Re, are not considerably influenced when one third of DOPC molecules is substituted with CHOL (DOPC:CHOL = 2:1). Constituents of buffer (50 mmol/dm3 PBS, 150 mmol/dm3 NaCl) caused aggregation of DOPC and DOPC-CHOL unilamellar liposomes at zero and low DDAO concentration, as was shown by SANS, turbidimetry and DIC microscopy. After solubilisation of bilayer structures by surfactant, mixed DOPC-DDAO and DOPC-CHOL-DDAO micelles with the shape of cylinders with elliptical cross section were detected.

Source: General Physiology and Biophysics

DOI: 10.4149/gpb_2019056

Authors: Katarína Želinská, Jana Gallová, Silvia Huláková, Daniela Uhríková, Oleksandr Ivankov

Institutions: Institut Laue-Langevin, Comenius University Bratislava, Moscow Institute of Physics and Technology, Joint Institute for Nuclear Research, Institute for Safety Problems of Nuclear Power Plants

Language: English

Topic: Lipid Membrane Structure and Behavior

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: diamond