Curcumin is a modulator of bilayer material properties

Helgi I Ingolfsson, Roger E Koeppe, Olaf S Andersen

Research output: Contribution to journalArticleAcademicpeer-review

119 Citations (Scopus)

Abstract

Curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) is the major bioactive compound in turmeric (Curcuma longa) with antioxidant, antiinflammatory, anticarcinogenic, and antimutagenic effects. At low muM concentrations, curcumin modulates many structurally and functionally unrelated proteins, including membrane proteins. Because the cell membranes' lipid bilayer serves as a gate-keeper and regulator of many cell functions, we explored whether curcumin modifies general bilayer properties using channels formed by gramicidin A (gA). gA channels form when two monomers from opposing monolayers associate to form a conducting dimer with a hydrophobic length that is less than the bilayer hydrophobic thickness; gA channel formation thus causes a local bilayer thinning. The energetic cost of this bilayer deformation alters the gA monomer <--> dimer equilibrium, which makes the channels' appearance rate and lifetime sensitive to changes in bilayer material properties, and the gA channels become probes for changes in bilayer properties. Curcumin decreases bilayer stiffness, increasing both gA channel lifetimes and appearance rates, meaning that the energetic cost of the gA-induced bilayer deformation is reduced. These results show that curcumin may exert some of its effects on a diverse range of membrane proteins through a bilayer-mediated mechanism.

Original languageEnglish
Pages (from-to)10384-91
Number of pages8
JournalBiochemistry
Volume46
Issue number36
DOIs
Publication statusPublished - 11-Sep-2007
Externally publishedYes

Keywords

  • Curcumin
  • Electric Conductivity
  • Electrolytes
  • Gramicidin
  • Ion Channel Gating
  • Ion Channels
  • Lipid Bilayers
  • Membrane Proteins
  • Models, Biological

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