title: Transmembrane helix uniformity examined by spectral mapping of torsion angles.
abstract: The environment and unique balance of molecular forces within lipid bilayers has a profound impact upon the structure, dynamics, and function of membrane proteins. We describe the biophysical foundations for the remarkable uniformity of many transmembrane helices that result from the molecular interactions within lipid bilayers. In fact, the characteristic uniformity of transmembrane helices leads to unique spectroscopic opportunities allowing for phi,psi torsion angles to be mapped directly onto solid state nuclear magnetic resonance (NMR) PISEMA spectra. Results from spectral simulations, the solid state NMR-derived structure of the influenza A M2 proton channel transmembrane domain, and high-resolution crystal structures of 27 integral membrane proteins demonstrate that transmembrane helices tend to be more uniform than previously thought. The results are discussed through the definition of a preferred range of backbone varphi,psi torsion angles for transmembrane alpha helices and are presented with respect to improving biophysical characterizations of integral membrane proteins.
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4390, USA.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Page
authors.forename: Sanguk
authors.initials: S
authors.lastname: Kim
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Cross
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D009980:Influenza A virus / Q000737:chemistry; D008051:Lipid Bilayers / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D017433:Protein Structure, Secondary; D011522:Protons; D013059:Spectrum Analysis, Raman; D014763:Viral Matrix Proteins / Q000737:chemistry
chemical_list: D008051:Lipid Bilayers; D008565:Membrane Proteins; D011522:Protons; D014763:Viral Matrix Proteins