Unveiling the membrane-binding properties of N-terminal and C-terminal regions of G protein-coupled receptor kinase 5 by combined optical spectroscopies

Abstract

G protein-coupled receptor kinase 5 (GRK5) is thought to associate with membranes in part via N- and C-terminal segments that are typically disordered in available high-resolution crystal structures. Herein we investigate the interactions of these regions with model cell membrane using combined sum frequency generation (SFG) vibrational spectroscopy and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. It was found that both regions associate with POPC lipid bilayers but adopt different structures when doing so: GRK5 residues 2-31 (GRK52-31) was in random coil whereas GRK5546-565 was partially helical. When the subphase for the GRK52-31 peptide was changed to 4..