Title

Unusual sponge phospholipids and their analogs. Synthesis and interactions with conventional phospholipids and cholesterol in model membranes

ORCiD

Nejat Düzgüneş: 0000-0001-6159-1391

Document Type

Article

Publication Title

Chemistry and Physics of Lipids

ISSN

0009-3084

Volume

47

Issue

3

DOI

10.1016/0009-3084(88)90010-2

First Page

165

Last Page

175

Publication Date

1-1-1988

Abstract

As reported earlier, the marine sponge phospholipids 1,2-di-5,9-hexacosadienoyl-sn-glycero-3-phosphocholine (PC: (26 : 2, 26 : 2)) and its phosphoethanolamine counterpart exclude cholesterol to a great extent from their liposomal bilayers. To understand the reason for this exclusion, shorter acyl chain analogs of these phospholipids were synthesized. Liposomes composed of PC (18 : 2, 18 : 2), PC (22 : 2, 22 : 2) or PC (24 : 2, 24 : 2), with the unique Δ5,9 unsaturation typical of sponge phospholipids, incorporated cholesterol Δ5,9-PE (24 : 2, 24 : 2) which also incorporated cholesterol, had a phase transition temperature identical to its PC counterpart. Differential scanning calorimetry indicated that Δ5,9-PC (26 : 2, 26 : 2) could incorporate 1-stearoyl-2-oleoyl-sn-glycerophosphocholine PC (18 : 0, 18 : 1) into its bilayers at various ratios (20, 40, 60, 80 mol%), but part of PC (18 : 0, 18: 1) displayed monotectic behavior. When 20 mol cholesterol was added to thesemixtures, the sterol interacted preferentially with the PC (18 : 0, 18 : 1) but was also incorporated in all ratios into the mixture of phospholipids and created one major transition endotherm. © 1988.

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