Mesoscopic Structure in the Chain-melting Regime of Anionic Phospholipid Vesicles: DMPG
Overview
Authors
Affiliations
In a range of low ionic strength, aqueous dispersions of the anionic phospholipid DMPG (dimyristoylphosphatidylglycerol) have a transparent intermediate phase (IP, between T(m)(on) congruent with 20 degrees C and T(m)(off) congruent with 30 degrees C) between the turbid gel and fluid membrane phases, evidenced in turbidity data. Small angle x-ray scattering results on DMPG dispersions show that, besides the bilayer peak present in all phases, a peak corresponding to a mesoscopic structure at approximately 400 A is detected only in IP. The dependence of this peak position on DMPG concentration suggests a correlation in the bilayer plane, consistent with the stability of vesicles in IP. Moreover, observation of giant DMPG vesicles with phase contrast light microscopy show that vesicles "disappear" upon cooling below T(m)(off) and "reappear" after reheating. This further proves that although vesicles cannot be visualized in IP, their overall structure is maintained. We propose that the IP in the melting regime corresponds to unilamellar vesicles with perforations, a model which is consistent with all described experimental observations. Furthermore, the opening of pores across the membrane tuned by ionic strength, temperature, and lipid composition is likely to have biological relevance and could be used in applications for controlled release from nanocompartments.
Supramolecular Aggregates: Hardness Plus Softness.
do Amaral L Molecules. 2021; 26(14).
PMID: 34299507 PMC: 8305938. DOI: 10.3390/molecules26144233.
Enhanced dynamics in the anomalous melting regime of DMPG lipid membranes.
Kelley E, Nagao M, Butler P, Porcar L, Farago B Struct Dyn. 2020; 7(5):054704.
PMID: 33094128 PMC: 7568673. DOI: 10.1063/4.0000031.
Lipid membrane templated misfolding and self-assembly of intrinsically disordered tau protein.
Majewski J, Jones E, Vander Zanden C, Biernat J, Mandelkow E, Chi E Sci Rep. 2020; 10(1):13324.
PMID: 32770092 PMC: 7414892. DOI: 10.1038/s41598-020-70208-6.
Galassi V, Salinas S, Montich G Eur Biophys J. 2017; 47(2):165-177.
PMID: 28752207 DOI: 10.1007/s00249-017-1243-5.
Akter N, Radiman S, Mohamed F, Abdul Rahman I, Reza M Sci Rep. 2012; 1:71.
PMID: 22355590 PMC: 3216558. DOI: 10.1038/srep00071.