Figure 1.
Glycosides used in the simulation: (a) βMal-C12 (b) βCel-C12 and (c) βIsoMal-C12 (d) βBCMal-C12C10.
Starting from glycosidic oxygen, each glycolipid's main alkyl chain (sn-1) is labeled from C71 to C82 and the branched chain (sn-2) from C83 to C92. Here, for clarity we have reduced the atoms' labels on the sugar, a slight modification from the standard nomenclature according to IUPAC given in Figure 1 of [22].
Table 1.
Average values at 27°C of the simulated area per lipid, A and the bilayer spacing, d.
Figure 2.
Radial distribution function for three carbon atoms along the alkyl chain for monoalkylated lipids: (a) βMal-C12 (b) βCel-C12 and (c) βIsoMal-C12.
Figure 3.
Snapshot of chain vectors between midpoints of C71–C72 and C80–C81 for monoalkylated lipids and chain sn-1.
For chain sn-2, the vector is defined between midpoints of C71–C72 and C90–C91.
Figure 4.
Fractional gauche population in, P(gauche), for dihedral angles between carbons in the alkyl chains.
The dihedral angle label, for example C71–C74 represent C71–C72–C73–C4 following alkyl chain numbering in Figure 1. (a) βMal-C12, (b) βCel-C12, (c) βIsoMal-C12, (d) βBCMal-C12C10(sn-1), and (e) βBCMal-C12C10(sn-2). First lipid layer (□), second layer (×), third layer (+), and fourth layer (*).
Figure 5.
Correlation times as a function of each C–H vector along lipid alkyl chains are shown.
The labeling of carbon atoms follows the naming convention as in Figure 1. (a) shows the correlation times for monoalkylated glycolipids, βMal-C12 (+), βCel-C12 (×), and βIsoMal-C12 (*). (b) and (c) show correlation times for chains sn-1 and sn-2 respectively for βBCMal-C12C10.
Figure 6.
Average correlation time of sugar headgroup of lipids: reducing sugar (ring1); non-reducing sugar (ring2); and combination of ring1 and ring2 (ring12).
Figure 7.
Distributions of alkyl chain tilt angle θ of various glycolipids for one layer.
Shows the current results for 160βMal-C12, black for βBCMal-C12C10 (sn-1), deep sky blue for βBCMal-C12C10(sn-2), green for βCel-C12 and dark blue for βIsoMal-C12.
Figure 8.
Some lipids' conformations and bilayer snapshots from the simulation.
(a) Three possible lipid conformations with the chain tilt angle, θ of 24° and 156°. (b) The dispersion interaction observed from two viewing angles, between the C–H from the sugar face and those of the alkyl chain by a representative lipid (enlarged) from the third layer. (c) A characteristic example of the sugar headgroup region (t = 140 ns) from the third leaflet showing the hydrophobic cavity (top-view). (d) The time evolution of a typical side-view of the second and third leaflets. The lipid (drawn fully with VDW model) is seen to work itself into the hydrophilic region.