A stereochemical model for phospholipids. II: Conformational analysis and molecular packing of phosphatidylethanolamine (PE)

✍ Scribed by A.L. Kovacs; E. Brosio; F. Conti; A. Di Nola; G. Napolitano

• Publisher: Elsevier Science
• Year: 1980
• Tongue: English
• Weight: 584 KB
• Volume: 27
• Category: Article
• ISSN: 0009-3084
• DOI: 10.1016/0009-3084(80)90017-1

✦ Synopsis

A partition energy method procedure was applied to select the energetically favoured conformations of phosphatidylethanolamine WE) as polar constituents of phospholipid molecules. The result indicated a large degree of freedom for the two torsion angles of the ester bond of the phosphate and a gauche, gauche star conformation for the ethane bond.

A packing process of the molecule was carried out through a potential energy calculation by considering the conformers selected above, using previously published procedure and conventions. All the arrangements which possess the best packing energy values were characterised by an orientation of the P--N dipolar segment parallel to the lattice plain. Rotation of the internal torsion angles and rotation in the eulerian space of the molecule produced differences in the charged groups that interact. An additional minimum was present in the energy packing process of those conformers which have the first torsion angle of the phosphate in a trans conformation. This minimum, which corresponds to an orientation of the molecule orthogonal to the lattice plane, requires a complete neutralisation of the point charges on the system.

The results of the calculation underline the importance of changes in the behaviour of the polar group of the phospholipids in the packing process.