33 documents found, page 1 of 4
Fluorescent Probes cis- and trans-Parinaric Acids in Fluid and Gel Lipid Bilaye...
Oliveira, Alexandre C.; Filipe, Hugo A. L.; Loura, Luís M. S.Fluorescence probes are indispensable tools in biochemical and biophysical membrane studies. Most of them possess extrinsic fluorophores, which often constitute a source of uncertainty and potential perturbation to the host system. In this regard, the few available intrinsically fluorescent membrane probes acquire increased importance. Among them, cis- and trans-parinaric acids (c-PnA and t-PnA, respectively) s...
Permeation of a Homologous Series of NBD-Labeled Fatty Amines through Lipid Bil...
Filipe, Hugo A. L.; Loura, Luís M. S.; Moreno, Maria JoãoPermeation through biomembranes is ubiquitous for drugs to reach their active sites. Asymmetry of the cell plasma membrane (PM) has been described as having an important role in this process. Here we describe the interaction of a homologous series of 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD)-labeled amphiphiles (NBD-Cn, n = 4 to 16) with lipid bilayers of different compositions (1-palmitoyl, 2-oleoyl-sn-glycero-3...
Interaction of a Homologous Series of Amphiphiles with P-glycoprotein in a Memb...
Moreno, Maria João; Filipe, Hugo A. L.; Cunha, Susana V. P.; Ramos, Cristiana V.; Martins, Patricia A. T.; Abel, Biebele; Loura, Luís M. S.The transport of drugs by efflux transporters in biomembranes limits their bioavailability and is a major determinant of drug resistance development by cancer cells and pathogens. A large number of chemically dissimilar drugs are transported, and despite extensive studies, the molecular determinants of substrate specificity are still not well understood. In this work, we explore the role of polar and non-polar ...
Interaction of Hoechst 33342 with POPC Membranes at Different pH Values
Cordeiro, Margarida M.; Filipe, Hugo A. L.; Santos, Patrícia dos; Samelo, Jaime Amadeu Cruz Reis; Ramalho, João P Prates; Loura, Luís M. S.Hoechst 33342 (H33342) is a fluorescent probe that is commonly used to stain the DNA of living cells. To do so, it needs to interact with and permeate through cell membranes, despite its high overall charge at physiological pH values. In this work, we address the effect of pH in the association of H33342 with lipid bilayers using a combined experimental and computational approach. The partition of H33342 to 1-p...
Interactions between Rhodamine Dyes and Model Membrane Systems — Insights from ...
Magalhães, Nisa; Simões, Guilherme M.; Cristiana, Ramos; Samelo, Jaime; Oliveira, Alexandre C.; Filipe, Hugo A. L.; Prates Ramalho, João P.Background: rhodamines are dyes widely used as fluorescent tags in cell imaging, probing of mitochondrial membrane potential, and as P-glycoprotein model substrates. In all these applications, detailed understanding of the interaction between rhodamines and biomembranes is fundamental. Methods: we combined atomistic molecular dynamics (MD) simulations and fluorescence spectroscopy to characterize the interactio...
Molecular Dynamics Simulations: Advances and Applications
Filipe, Hugo A. L.; Loura, Luís M. S.Molecular dynamics (MD) simulations have led to great advances in many scientific disciplines, such as chemical physics, materials science, and biophysics [...].
Analysis of the equilibrium distribution of Ligands in Heterogeneous Media – Ap...
Moreno, Maria João; Loura, Luís M. S.; M. Martins, Jorge; Salvador, Armindo; Velazquez-Campoy, AdrianThe equilibrium distribution of small molecules (ligands) between binding agents in heterogeneous media is an important property that determines their activity. Heterogeneous systems containing proteins and lipid membranes are particularly relevant due to their prevalence in biological systems, and their importance to ligand distribution, which, in turn, is crucial to ligand’s availability and biological activi...
The Secret Lives of Fluorescent Membrane Probes as Revealed by Molecular Dynami...
Filipe, Hugo A. L.; Moreno, Maria João; Loura, Luís M. S.Fluorescent probes have been employed for more than half a century to study the structure and dynamics of model and biological membranes, using spectroscopic and/or microscopic experimental approaches. While their utilization has led to tremendous progress in our knowledge of membrane biophysics and physiology, in some respects the behavior of bilayer-inserted membrane probes has long remained inscrutable. The ...
Interaction of Bile Salts With Lipid Bilayers: An Atomistic Molecular Dynamics ...
Neves, Maria C.; Filipe, Hugo A. L.; Reis, Rita Leones; Prates Ramalho, João P.; Coreta-Gomes, Filipe Manuel; Moreno, Maria João; Loura, Luís M. S.Bile salts (BS) are biosurfactants crucial for emulsification and intestinal absorption of cholesterol and other hydrophobic compounds such as vitamins and fatty acids. Interaction of BS with lipid bilayers is important for understanding their effects on membranes properties. The latter have relevance in passive diffusion processes through intestinal epithelium such as reabsorption of BS, as well as their degre...
Fluorescence of nitrobenzoxadiazole (NBD)-labeled lipids in model membranes is ...
Amaro, Mariana; Filipe, Hugo A. L.; Prates Ramalho, J. P.; Hof, Martin; Loura, Luís M. S.Nitrobenzoxadiazole (NBD)-labeled lipids are popular fluorescent membrane probes. However, the understanding of important aspects of the photophysics of NBD remains incomplete, including the observed shift in the emission spectrum of NBD-lipids to longer wavelengths following excitation at the red edge of the absorption spectrum (red-edge excitation shift or REES). REES of NBD-lipids in membrane environments ha...