Geometrical effects of phospholipid olefinic bonds on the structure and dynamics of membranes: A molecular dynamics study

Abstract

The trans isomers of fatty acids are found in human adipose tissue. These isomers have been linked with deleterious health effects (e.g., coronary artery disease). In this study, we performed molecular dynamics simulations to investigate the structures and dynamic properties of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC) and 1-palmitoyl-2-elaidoyl sn-glycero-3-phosphatidylcholine (PEPC) lipid bilayers. The geometry of the olefinic bond and membrane packing effects significantly influenced the conformations and dynamics of the two C-C single bonds adjacent to the olefinic bond. For the PEPC lipid, the two C-C single bonds adjacent to the olefinic bond adopted mainly nonplanar skew-trans and planar cis-trans motifs; although the cis conformation featured relatively strong steric repulsion, it was stabilized through membrane packing because its planar structure is more suitable for membrane packing. Moreover, membrane packing effects stabilized the planar transition state for conformational conversion to a greater extent than they did with the nonplanar transition state, thereby affecting the dynamics of conformational conversion. The rotational motions of the first neighboring C-C single bonds were much faster than those of typical saturated C-C single bonds; in contrast, the rotational motions of the second neighboring C-C single bonds were significantly slower than those of typical saturated torsion angles. The packing of PEPC lipids is superior to that of POPC lipids, leading to a smaller area per lipid, a higher order parameter and a smaller diffusion coefficient. The distinct properties of POPC and PEPC lipids result in PEPC lipids forming microdomains within a POPC matrix.

The Location of the Protonated and Unprotonated Forms of Arbidol in the Membrane: A Molecular Dynamics Study

“…and z-( Fig. S2A and S2B, respectively), in agreement with the profiles observed earlier for experimental and simulated data (Bockmann et al 2003;Klauda et al 2010;Tsai et al 2015). The same can be said for the average -S CD values of the sn-1 of POPG in the same system (Fig.…”

Procyanidin C1 Location, Interaction, and Aggregation in Two Complex Biomembranes

“…When there is complete disorder, the S CD value is 0, and a value of 0.5 specifies full order along the normal bilayer [ 56 ]. The average –S CD values of the acyl chains of all of the phospholipids in the PM model system, i.e., POPC, POPE, POPS, PI-3P, and PSM, were in agreement with the profiles that were observed earlier for the experimental and simulated data [ 36 , 57 , 58 ] ( Supplementary Figure S10 ). However, for some of the phospholipids that were near to the PC1 molecules, there were significant, although not dramatic, changes in the S CD profiles.…”

Thermosensitive Vesicles from Chemically Encoded Lipid‐Grafted Elastin‐like Polypeptides

“…The olefin bond present in natural lipids/fatty acids has a significant impact on the membrane packing and on its fluidity owing to the conformational ( cis / trans ) difference [36] . The planar structure, torsion angle and faster rotational motions of the first neighboring single C−C bonds on the cis alkyl chains have a significant impact on the formation of well‐packed lipid bilayers in natural cell membranes [36] . Whereas the trans conformation behaves similar to saturated fatty acids [36] .…”

“…The planar structure, torsion angle and faster rotational motions of the first neighboring single C−C bonds on the cis alkyl chains have a significant impact on the formation of well‐packed lipid bilayers in natural cell membranes [36] . Whereas the trans conformation behaves similar to saturated fatty acids [36] . ATR FTIR spectroscopy was used to confirm the presence of the characteristic =C−H stretching vibration band of the cis conformation at 3005 cm −1 and the absence of the trans conformation band at 3034 cm −1 (Supporting Information, Figure S2) [34] …”

“…Considering the temperature responsive property of ELP[M 1 V 3 ‐ 40 ], [32] a monounsaturated aliphatic tail [35] with a low melting transition temperature ( T m =−25 °C; Supporting Information, Figure S6) was selected in order to not interfere with the phase transition temperature ( T cp ) of the ELP. The olefin bond present in natural lipids/fatty acids has a significant impact on the membrane packing and on its fluidity owing to the conformational ( cis / trans ) difference [36] . The planar structure, torsion angle and faster rotational motions of the first neighboring single C−C bonds on the cis alkyl chains have a significant impact on the formation of well‐packed lipid bilayers in natural cell membranes [36] .…”