Comparing the Structural Topology of Integral and Peripheral Membrane Proteins Utilizing Electron Paramagnetic Resonance Spectroscopy

摘要

The alignment of membrane proteins in lipid bilayers can provide pertinent structural and dynamic information. Structural topology data gleaned from such studies can be used to help determine the functional mechanisms associated with a wide variety of integral membrane proteins. Significant progress in alignment studies has been made utilizing solid-state NMR (SSNMR) and more recently electron paramagnetic resonance (EPR) spectroscopy. In this communication, we successfully demonstrate, for the first time, the determination of the structural topology and helical tilt of an antimicrobial peptide (magainin 2) that lies on the membrane surface using aligned X-band spin-label EPR spectroscopic techniques. The corresponding EPR hyperfine splitting and line shapes are in sharp contrast to a hydrophobic integral membrane protein such as the M2δ acetylcholine receptor.