Alzheimer's disease (AD) is related to the fibrillation of the Aβ peptides at neuronal membranes, a process that depends on the lipid composition and may impart different physical states to the membrane. In the present work, we study the properties of the Aβ peptide when mixed with a zwitterionic lipid (DMPC), using the Langmuir monolayer technique as an approach to control membrane physical conditions. First, we build on previous characterizations of pure Aβ monolayers and observe that, in addition to high shear, these films present a pronounced compressional hysteresis.
View Article and Find Full Text PDFThe behavior of amphiphilic molecules such as lipids, peptides and their mixtures at the air/water interface allow us to evaluate and visualize the arrangement formed in a confined and controlled surface area. We have studied the surface properties of the zwitterionic DPPC lipid and Aβ(1-40) amyloid peptide in mixed films at different temperatures (from 15 to 40 °C). In this range of temperature the surface properties of pure Aβ(1-40) peptide remained unchanged, whereas DPPC undergoes its characteristic liquid-expanded → liquid-condensed bidimensional phase transition that depends on the temperature and lateral pressure.
View Article and Find Full Text PDFViviana A. Cavieres and Gonzalo A. Mardones were not included as authors in the original publication [.
View Article and Find Full Text PDFBiochim Biophys Acta Proteins Proteom
July 2023
A novel mathematical development applied to protein ligand binding thermodynamics is proposed, which allows the simulation, and therefore the analysis of the effects of multiple and independent binding sites to the Native and/or Unfolded protein conformations, with different binding constant values. Protein stability is affected when it binds to a small number of high affinity ligands or to a high number of low affinity ligands. Differential scanning calorimetry (DSC) measures released or absorbed energy of thermally induced structural transitions of biomolecules.
View Article and Find Full Text PDFSepsis is a worldwide severe disease with a high incidence and mortality rate. Sepsis is a frequent cause of admission to the emergency department (ED). Although prognostic scores (Sequential Organ Failure Assessment, SOFA; New Early Warning Score, NEWS; Rapid Emergency Medicine Score, REMS) are commonly used for risk stratification in septic patients, many of these scores are of poor utility in the ED.
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