Methods for studying transmembrane peptides in bicelles: consequences of hydrophobic mismatch and peptide sequence

Abstract

We have shown that bicelles prepared from dilauryl phosphatidylcholine (DLPC) and dipalmitoyl phosphatidylcholine (DPPC) align in a magnetic field under conditions similar to the more common dimyristoyl phosphatidylcholine (DMPC) bicelles. In addition, a model transmembrane peptide, P16, with a hydrophobic stretch of 24 A A, and specific alanine-d 3 labels, was incorporated into all of the different bicelles. The long-chain phospholipid (DLPC, DMPC, or DPPC) remained unperturbed upon incorporation of the peptide while the quadrupolar splitting of the short-chain phospholipid along the bicelle rim increased by varying degrees in the different bicelle systems. The change in quadrupolar splitting of the short-chain phospholipids was attributed to changes in either fluidity of the planar region of the bicelle or differences in overall lipid packing. When the hydrophobic stretch of the bilayer was 22.8 (DMPC) or 26.3 A A (DPPC), the peptide tilt was found to be transmembrane (33-35°with respect to the bicelle normal). When the hydrophobic stretch of the bilayer was 19.5 A A (DLPC), the peptide quadrupolar splittings suggested a loss of transmembrane orientation. When tryptophan was incorporated in the middle of the transmembrane region, the transmembrane orientation was also lost.

The Magic of Bicelles Lights Up Membrane Protein Structure

“…206 The 22-residue model peptide P16 assumes a transmembrane orientation as determined by amide–water chemical exchange and lipid NOEs. 207 (A parallel solid-state investigation on P16 208 is described below. )…”

When detergent meets bilayer: Birth and coming of age of lipid bicelles

“…One important characteristic of biological membranes is their bilayer thickness, which affects embedded proteins by means of hydrophobic mismatch [103,21]. Bicelles with different bilayer thickness have successfully been prepared [103]. The effect of varying chain-length in both lipid and detergent components has been investigated systematically [101].…”

Bicelles as model membranes for solid‐ and solution‐state NMR studies of membrane peptides and proteins

“…This was also done to compare the position and verify the preferential interaction of Metenkephalin in zwitterionic and negatively charged bicelles (29). The insertion of the helicoidal transmembrane peptide P16 was also investigated using 2 H NMR (23).…”