Ballesteros, U.; González-Ramirez, E.J.; de la Arada, I.; Sot, J.; Etxaniz, A.; Goñi, F.M.; Alonso, A.; Montes, L.R. Effects of a N-maleimide-derivatized Phosphatidylethanolamine on the Architecture and Properties of Lipid Bilayers †. Int. J. Mol. Sci.2023, 24, 16570.
Ballesteros, U.; González-Ramirez, E.J.; de la Arada, I.; Sot, J.; Etxaniz, A.; Goñi, F.M.; Alonso, A.; Montes, L.R. Effects of a N-maleimide-derivatized Phosphatidylethanolamine on the Architecture and Properties of Lipid Bilayers †. Int. J. Mol. Sci. 2023, 24, 16570.
Ballesteros, U.; González-Ramirez, E.J.; de la Arada, I.; Sot, J.; Etxaniz, A.; Goñi, F.M.; Alonso, A.; Montes, L.R. Effects of a N-maleimide-derivatized Phosphatidylethanolamine on the Architecture and Properties of Lipid Bilayers †. Int. J. Mol. Sci.2023, 24, 16570.
Ballesteros, U.; González-Ramirez, E.J.; de la Arada, I.; Sot, J.; Etxaniz, A.; Goñi, F.M.; Alonso, A.; Montes, L.R. Effects of a N-maleimide-derivatized Phosphatidylethanolamine on the Architecture and Properties of Lipid Bilayers †. Int. J. Mol. Sci. 2023, 24, 16570.
Abstract
N-maleimide-derivatized phospholipids are often used to facilitate protein anchoring to membranes. In autophagy studies, this is applied to the covalent binding of Atg8, an autophagy protein, to a phosphatidylethanolamine (PE) in the nascent autophagosome. However, the question remains on how closely the N-maleimide PE derivative (PE-mal) mimicks the native PE in the bilayer. In the present paper, spectroscopic and calorimetric techniques have been applied to vesicles containing either PE or PE-mal (together with other phospholipids) to compare the properties of the native and derivatized forms of PE. According to differential scanning calorimetry, and to infrared spectroscopy, the presence of PE-mal did not perturb the fatty acyl chains in the bilayer. Fluorescence spectroscopy and microscopy showed that PE-mal did not alter bilayer permeability either. However, fluorescence emission polarization of Laurdan and DPH probes indicated an increased order, or decreased fluidity, in the bilayers containing PE-mal. In addition, infrared spectral data from the phospholipid phosphate region revealed a PE-mal-induced conformational change of the polar heads, accompanied by an increased hydration. Globally considered, the results suggest that PE-mal would be a reasonable substitute for PE in model membranes containing reconstituted proteins.
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