Vibrational spectroscopy combined with molecular dynamics simulations as a tool for studying behavior of reactive aldehydes inserted in phospholipid bilayers

Abstract

Vibrational Fourier-transform infrared (FTIR) spectroscopy aided with molecular dynamics (MD) simulations is used for studying the interaction of several reactive aldehydes (RAs), nonanal (NA), 2-nonenal (NE), 4-hydroxy-2-nonenal (HNE) and 4-oxo-2-nonenal (ONE), with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayer. The results obtained by the combination of these two techniques, supported also by electron paramagnetic resonance (EPR) spectroscopy, show that NA has the strongest stabilization in the bilayer, followed by less stabilized NE, HNE and ONE. We also revealed that HNE readily makes hydrogen bonds to carbonyl groups of POPC (but not to phosphate groups), in contrast to other RAs which are hydrogen bond acceptors and do not make hydrogen bonds with lipids. A combination of FTIR spectroscopy and MD simulations is sensitive to small chemical changes in the structures of RAs, thus making it a valuable tool for studying the weak interactions between compounds inserted to phospholipid bilayers.

Keywords: Hydrogen bonding; Magnetic resonance spectroscopy; Molecular dynamics simulations; Phospholipid bilayer; Reactive aldehydes; Vibrational spectroscopy.