The dissipative quartz crystal microbalance technique is a simple and label-free approach to measure simultaneously the mass uptake and viscoelastic properties of the absorbed/immobilized mass on sensor surfaces, allowing the measurements of the interaction of proteins with solid-supported surfaces, such as lipid bilayers, in real-time and with a high sensitivity. Annexins are a highly conserved group of phospholipid-binding proteins that interact reversibly with the negatively charged headgroups via the coordination of calcium ions. Here, we describe a protocol that was employed to quantitatively analyze the binding of annexin A2 (AnxA2) to planar lipid bilayers prepared on the surface of a quartz sensor. This protocol is optimized to obtain robust and reproducible data and includes a detailed step-by-step description. The method can be applied to other membrane-binding proteins and bilayer compositions.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.3791/58224 | DOI Listing |
Int J Nanomedicine
January 2025
State Key Laboratory of Pathogenesis Prevention and Treatment of High Incidence Diseases in Central Asia, School of Medical Engineering and Technology Xinjiang Medical University, Urumqi, 830011, People's Republic of China.
Purpose: A synergistic treatment strategy of phototherapy and chemotherapy has been shown to improve efficacy and offer unique advantages over monotherapy. The purpose of this study is to explore a new nanocarrier system with liposome as the inner membrane and erythrocyte membrane as the outer membrane, which aims to realize the leak-free load of phototherapy drug indocyanine green (ICG) and chemotherapy drug doxorubicin (DOX), prolong the circulation time in vivo and improve the therapeutic effect.
Patients And Methods: In this study, bilayer membrane-loaded ICG and DOX nanoparticles (RBC@ICG-DOX NPs) were prepared and characterized.
J Biol Inorg Chem
January 2025
Department of Chemistry and Biochemistry, Miami University, Oxford, OH, USA.
Lipid nanoparticles formed with copolymers are a new and increasingly powerful tool for studying membrane proteins, but the extent to which these systems affect the physical properties of the membrane is not completely understood. This is critical to understanding the caveats of these new systems and screening for structural and functional artifacts that might be caused in the membrane proteins they are used to study. To better understand these potential effects, the fluid properties of dipalmitoylphosphatidylcholine lipid bilayers were examined by electron paramagnetic resonance (EPR) spectroscopy with spin-labeled reporter lipids in either liposomes or incorporated into nanoparticles with the copolymers diisobutylene-maleic acid or styrene maleic acid.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390.
Neurotransmitter release is triggered in microseconds by Ca-binding to the Synaptotagmin-1 C-domains and by SNARE complexes that form four-helix bundles between synaptic vesicles and plasma membranes, but the coupling mechanism between Ca-sensing and membrane fusion is unknown. Release requires extension of SNARE helices into juxtamembrane linkers that precede transmembrane regions (linker zippering) and binding of the Synaptotagmin-1 CB domain to SNARE complexes through a "primary interface" comprising two regions (I and II). The Synaptotagmin-1 Ca-binding loops were believed to accelerate membrane fusion by inducing membrane curvature, perturbing lipid bilayers, or helping bridge the membranes, but SNARE complex binding through the primary interface orients the Ca-binding loops away from the fusion site, hindering these putative activities.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Universite Libre de Bruxelles, Engineering of Molecular NanoSystems, Avenue F. Roosevelt 50, 1050, Brussels, BELGIUM.
Artificial anion transporters offer a potential way to treat deficiencies in cellular anion transport of genetic origins. In contrast to the large variety of mobile anion carriers and self-assembled anion channels reported, unimolecular anion channels are less investigated. Herein, we present a unique example of a unimolecular anion channel based on a bambusuril (BU) macrocycle, a well-established anion receptor.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
In this work, a model for anisotropic interactions between proteins and cellular membranes is proposed for large-scale continuum simulations. The framework of the model is based on dynamic density functional theory, which provides a formalism to describe the lipid densities within the membrane as continuum fields while still maintaining the fidelity of the underlying molecular interactions. Within this framework, we extend recent results to include the anisotropic effects of protein-lipid interactions.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!