Distribution of long/short lipids near transmembrane peptides
Participating Group members : Fuchang Yin

Top (left) and cross-sectional (right) views of snapshots of final simulation structures of NeuTM35 peptide in mixed DMPC-DDPC bilayers. Average DMPC composition is 55.8%. Green, blue, and red represent peptide, DMPC, and DDPC respectively. Phosphorus atoms are shown as spheres in the right-hand panels. Water is omitted for clarity

Transmembrane peptides, or protein segments, typically consist of a hydrophobic region flanked by hydrophilic regions. Providing an appropriate environment for all regions of a TM peptide can involve local distortions of the bilayer thickness to resolve any "hydrophobic mismatch" between the length of the hydrophobic segment and the thickness of the bilayer's hydrophobic interior. In a mixed bilayer, these distortions may attract or repel lipids with different properties, producing local deviations in composition. Experimental investigations over many years using a range of experimental approaches have come to different conclusions about the degree of such sorting effects. Our MCMD Simulations of the transmembrane helix gramicidin A in DSPC/DMPC and DMPC/DDPC mixtures showed only a very weak sorting, with a local enrichment of the more favorable lipid of under 5%.(Yin & Kindt, 2010). Further simulations in progress on a larger beta-barrel peptide, OmpA, have yielded moderately stronger sorting effects.(Yin & Kindt, 2011, submitted to Biophysical Journal).  




>> Last modified on April 1, 2004.  Any question or Comment, please email to jkindt@emory.edu.