Effect of pH and Lipid Composition on Membrane-Spanning Helices with Glutamic Acid Examined by Solid-State Nmr

Abstract

Transmembrane proteins constitute about 30% of the proteins in the cell and are involved in major biological processes. The dynamic properties of membrane proteins and the ionization states of particular side chains are important for biological function. The biophysical properties of membrane proteins nevertheless can be difficult todecode, particularly for glutamic acid in the lipid environment of cell membranes (BBA Biomembranes 1859, 484). To study the ionization of glutamic acid in transmembrane peptides, guest glutamic acid residues were substituted into the well-defined model helix of GWALP23 (acetyl-GGAL4WLALALALALAL16ALWLAGA-amide).