Force Transduction and Lipid Binding in MscL: A Continuum-Molecular Approach
Examination of the structure of integral membrane proteins including MscL, the human mechanosensitive K2P1 channel TWIK-1 , the photo-sensitive G protein-coupled receptor bovine rhodopsin , and the human dopamine D3 G protein-coupled receptor . These proteins show the occurrence of a common structural motif, where phospholipids may bind and anchor the protein to the bilayer. The lipid binding motif is composed of a short amphipathic helix (10–15 amino acids) at either the N or C-terminus, which is followed by a sharp bend and a trans-membrane helix. The short amphipathic helix typically contains one or more closely spaced Phe residues on the hydrophobic face, and multiple Lys and sometimes Arg (positively charged) residues on the hydrophilic side.