Physiological Calcium Concentrations Slow Dynamics at the Lipid-Water Interface
| Autor: | Mason L. Valentine, Ron Elber, Carlos R. Baiz, Alfredo E. Cardenas |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Lipid Bilayers
Biophysics Phospholipid chemistry.chemical_element Phosphatidylserines Calcium Molecular Dynamics Simulation 010402 general chemistry 01 natural sciences Divalent chemistry.chemical_compound Phosphatidylcholine 0103 physical sciences Extracellular Lipid bilayer chemistry.chemical_classification Membranes 010304 chemical physics Water Phosphatidylserine 0104 chemical sciences Membrane chemistry Phosphatidylcholines |
| Popis: | Phospholipids can interact strongly with ions at physiological concentrations, and these interactions can alter membrane properties. Here, we describe the effects of calcium ions on the dynamics in phospholipid membranes. We used a combination of time-resolved ultrafast two-dimensional infrared spectroscopy and molecular dynamics simulations. We found that millimolar Ca 2+ concentrations lead to slower fluctuations in the local environment at the lipid-water interface of membranes with phosphatidylserine. The effect was only observed in bilayers containing anionic phosphatidylserine; membranes composed of only zwitterionic phosphatidylcholine did not experience a slowdown. Local water dynamics were measured using the ester groups as label-free probes and were found to be up to 50% slower with 2.5 mM Ca 2+ . Molecular dynamics simulations show that Ca 2+ primarily binds to the carboxylate group of phosphatidylserines. These findings have implications for apoptotic and diseased cells in which phosphatidylserine is exposed to extracellular calcium and for the biophysical effects of divalent cations on lipid bilayers. |
| Databáze: | OpenAIRE |
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