title: Cell-free expressed bacteriorhodopsin in different soluble membrane mimetics: biophysical properties and NMR accessibility.
abstract: Selecting a suitable membrane-mimicking environment is of fundamental importance for the investigation of membrane proteins. Nonconventional surfactants, such as amphipathic polymers (amphipols) and lipid bilayer nanodiscs, have been introduced as promising environments that may overcome intrinsic disadvantages of detergent micelle systems. However, structural insights into the effects of different environments on the embedded protein are limited. Here, we present a comparative study of the heptahelical membrane protein bacteriorhodopsin in detergent micelles, amphipols, and nanodiscs. Our results confirm that nonconventional environments can increase stability of functional bacteriorhodopsin, and demonstrate that well-folded heptahelical membrane proteins are, in principle, accessible by solution-NMR methods in amphipols and phospholipid nanodiscs. Our data distinguish regions of bacteriorhodopsin that mediate membrane/solvent contacts in the tested environments, whereas the protein's functional inner core remains almost unperturbed. The presented data allow comparing the investigated membrane mimetics in terms of NMR spectral quality and thermal stability required for structural studies.
authors: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.
authors: Manuel
authors: M
authors: Etzkorn
authors: Thomas
authors: T
authors: Raschle
authors: Franz
authors: F
authors: Hagn
authors: Vladimir
authors: V
authors: Gelev
authors: Amanda J
authors: AJ
authors: Rice
authors: Thomas
authors: T
authors: Walz
authors: Gerhard
authors: G
authors: Wagner
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D003470:Culture Media; D003902:Detergents / Q000737:chemistry; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D019617:Halobacterium salinarum / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008051:Lipid Bilayers / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008567:Membranes, Artificial; D008823:Micelles; D008958:Models, Molecular; D018716:Molecular Mimicry; D019906:Nuclear Magnetic Resonance, Biomolecular; D010743:Phospholipids / Q000737:chemistry; D017510:Protein Folding; D055550:Protein Stability; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012995:Solubility; D013347:Subcellular Fractions / Q000737:chemistry / Q000378:metabolism*
chemical_list: D003470:Culture Media; D003902:Detergents; D008051:Lipid Bilayers; D008565:Membrane Proteins; D008567:Membranes, Artificial; D008823:Micelles; D010743:Phospholipids; D011994:Recombinant Proteins; D001436:Bacteriorhodopsins