An Upside Down View of Cholesterol's Condensing Effect: Does Surface Occupancy Play a Role?

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Janout V., Turkyilmaz S., Wang M., Wang Y., Manaka Y., Regen S. L.

LANGMUIR, vol.26, no.8, pp.5316-5318, 2010 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 26 Issue: 8
  • Publication Date: 2010
  • Doi Number: 10.1021/la100878s
  • Journal Name: LANGMUIR
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.5316-5318
  • Middle East Technical University Affiliated: No

Abstract

The condensing action or cholesterol has been compared with that of a structural isomer having its hydroxyl group located at the C-25 position (i.e., 25-OH'), that is, an isomer favoring an "upside down" orientation in lipid membranes. Surface pressure area isotherms of mixed monolayers made from 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DM PC)/cholesterol and DM PC/25-OH' have established that 25-OH' has a weaker condensing effect than cholesterol. Nearest-neighbor recognition measurements in liposomes made from 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) have also shown that 25-OH' has a weaker condensing effect in the physiologically relevant fluid bilayer state. These findings provide support for surface occupancy playing a role in the condensing action of cholesterol.