Which type of lipid interaction is disrupted by methyl-β-cyclodextrin?
Lipid raft integrity pharmacologically perturbed using methyl beta cyclodextrin torus shaped oligosaccharide seven glucose units hydrophobic interior cavity zero point eight nanometer diameter fitting sterol. Cavity fits cholesterol high affinity one to two stoichiometry extracting sterol membrane into soluble inclusion complex without hydrolyzing phospholipids at low concentrations below ten millimolar preserving phospholipid mass. Removal dismantles cholesterol sphingolipid condensed complexes driven van der Waals packing hydrogen bonding amide hydroxyl interactions transforming liquid ordered liquid disordered dispersing GPI anchored proteins caveolin flotillin abolishing cholera toxin B GM1 clustering visualized fluorescence microscopy FRET, FRAP diffusion increase. Peptide bonds protein synthesis ribosomes remain intact unrelated processes. Low concentrations selectively deplete raft cholesterol leaving bulk phospholipids, high doses extract phospholipids causing toxicity membrane blebbing. Repletion cholesterol loaded cyclodextrin restores rafts proving reversibility causality gold standard control. Reagent standard tool testing raft dependent signaling Src kinase activation HIV entry APP processing amyloid beta production demonstrating dependence microdomains cholesterol sphingolipid association rather than protein scaffold alone concept widely taught cell biology immunology virology courses and assay design for microdomains investigation and antiviral strategies.
Ref: Zidovetzki & Levitan, Biochim Biophys Acta 2007, Cyclodextrin cholesterol sphingolipid raft disruption mechanism and reversibility.