The membrane-induced structure of melittin is correlated with the fluidity of the lipids

• Published in: Biochimica et biophysica acta 2007, Vol.1768 (1), p.115-121
• Main Authors: Andersson, August, Biverståhl, Henrik, Nordin, Jon, Danielsson, Jens, Lindahl, Emma, Mäler, Lena
• Format: Article
• Language: English
• Subjects: Bicelle; Cholesterol; Cholesterol - chemistry; Cholic Acids - chemistry; Circular Dichroism; Detergents - chemistry; Dimyristoylphosphatidylcholine - chemistry; Helix transition; Lipid Bilayers - chemistry; Lipid Bilayers - metabolism; Magnetic Resonance Spectroscopy; Melitten - chemistry; Melitten - metabolism; Melittin; Membrane Fluidity; Membrane Lipids - chemistry; Membrane Lipids - metabolism; Molecular Conformation; NMR; Phospholipid Ethers - chemistry; Protein Binding; Protein Structure, Secondary; Relaxation; Spectrometry, Fluorescence; Spin Labels; Temperature
• ISSN: 0005-2736; 0006-3002; 1879-2642
• DOI: 10.1016/j.bbamem.2006.07.009

The effect of the bee toxin melittin on DMPC dynamics in fast-tumbling bicelles has been investigated. The 13C R 1 and 13C– 1H NOE relaxation parameters for DMPC were used to monitor the effect of melittin and cholesterol on lipid dynamics. It was found that melittin has the largest effect on the DMPC mobility in DMPC/DHPC bicelles, while less effect was observed in cholesterol-doped bicelles, or in bicelles made with CHAPS, indicating that the rigidity of the membrane affects the melittin–membrane interaction. CD spectra were analysed in terms of cooperativity of the α-helix to random coil transition in melittin, and these results also indicated similar differences between the bicelles. The study shows that bicelles can be used to investigate lipid dynamics by spin relaxation, and in particular of peptide-induced changes in membrane fluidity.