Protein-lipid interactions govern the structure and function of lipoprotein particles, which transport neutral lipids and other hydrophobic cargo through the blood stream. Apolipoproteins cover the surface of lipoprotein particles, including low-density (LDL) and high-density (HDL) lipoproteins, and determine their function. Previous work has focused on small peptides derived from these apolipoproteins or used such artificial lipid systems as Langmuir monolayers or the lipid disc assay to determine how apolipoproteins interact with the neutral lipid interface. Here, we focus on a recurring protein domain found in many neutral lipid-binding proteins, the amphipathic α-helix bundle. We use liquid droplet tensiometry to investigate protein-lipid interactions on an oil droplet, which mimics the real lipoprotein interface. The N-terminus of apoE 3 and full-length apoLp-III serve as model proteins. We find that each protein interacts with lipid monolayers at the oil-aqueous interface in unique ways. For the first time, we show that helix bundle unfolding is critical for proper protein insertion into the lipid monolayer at the oil-aqueous interface and that specific membrane lipids promote the rebinding of protein upon fluctuation in droplet size. These results shed new light on how amphipathic apolipoprotein α-helix bundles interact with neutral lipid particles.
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http://dx.doi.org/10.1021/acs.jpcb.1c00271 | DOI Listing |
J Phys Chem B
February 2024
Department of Chemistry and Biochemistry, Mount Allison University, 63C York Street, Sackville, New Brunswick E4L 1G8, Canada.
The self-assembly of gold nanoparticles (AuNPs) into thin films at the liquid-liquid interface has promising applications in industries such as catalysis, optics, and sensors. However, precise control over their formation is complex, influenced by several factors which scale differently with core size. Due to their small free energy of adsorption, there are few examples of AuNPs with core diameters <10 nm.
View Article and Find Full Text PDFData Brief
October 2023
Department of Petroleum Engineering, Covenant University, Canaan Land, Km 10 Idiroko Road, PMB 1023, Ota, Ogun State, Nigeria.
Surfactant flooding is adjudged one of the most promising chemicals enhanced oil recovery (cEOR) methods due to its high microscopic sweep efficiency. This surfactant shows high potential in mobilizing trapped residual oil (ganglia) through excellent lowering of the interfacial tension (IFT) between the crude oil-aqueous interface to ultra-low values while favorably altering the wettability (oil-wet to water-wet). Surfactant adsorption is a critical factor that determines how successful this cEOR method will be as well as the project economics.
View Article and Find Full Text PDFJ Phys Chem B
June 2023
Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
Anal Chem
March 2023
Bio-Functional Chemistry (UMR 7199), Institut du Médicament de Strasbourg, University of Strasbourg, 74 Route du Rhin, 67400 Illkirch-Graffenstaden, France.
Enzyme-linked immunosorbent assay (ELISA) is a central analytic method in biological science for the detection of proteins. Introduction of droplet-based microfluidics allowed the development of miniaturized, less-consuming, and more sensitive ELISA assays by coencapsulating the biological sample and antibody-functionalized particles. We report herein an alternative in-droplet immunoassay format, which avoids the use of particles.
View Article and Find Full Text PDFJ Phys Chem B
March 2022
Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
Molecular orientation plays a pivotal role in defining the functionality and chemistry of interfaces, yet accurate measurements probing this important feature are few, due, in part, to technical and analytical limitations in extracting information from molecular monolayers. For example, buried liquid/liquid interfaces, where a complex and poorly understood balance of inter- and intramolecular interactions impart structural constraints that facilitate the formation of supramolecular assemblies capable of new functions, are difficult to probe experimentally. Here, we use vibrational sum-frequency generation spectroscopy, numerical polarization analysis, and atomistic molecular dynamics simulations to probe molecular orientations at buried oil/aqueous interfaces decorated with amphiphilic oligomers.
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