Thermotropic properties of model membranes composed of polymerizable lipids. 1. Phosphatidylcholines containing terminal acryloyl, methacryloyl, and sorbyl groups

Abstract

The thermotropic phase behavior of hydrated bilayers of mono- and bis-substituted phosphatidylcholines (PC) containing either acryloyl, methacryloyl, or sorbyl ester groups at the chain terminus was studied by differential scanning calorimetry. Each of these compounds exhibits a single endotherm which occurs at a temperature lower than that of the main phase transition T m of the corresponding linear saturated chain PC. Variation of the chain length of the sorbylPCs results in a pronounced odd/even alternation of the T m . Consideration of the preferred conformation of glycerol ester lipids suggested by the crystal structure of dimyristoylPC dihydrate provides a basis for understanding the odd/even effect reported here