Elliptical structure of phospholipid bilayer nanodiscs encapsulated by scaffold proteins: casting the roles of the lipids and the protein.

Phospholipid bilayers host and support the function of membrane proteins and may be stabilized in disc-like nanostructures, allowing for unprecedented solution studies of the assembly, structure, and function of membrane proteins (Bayburt et al. Nano Lett. 2002, 2, 853-856). Based on small-angle neutron scattering in combination with variable-temperature studies of synchrotron small-angle X-ray scattering on nanodiscs in solution, we show that the fundamental nanodisc unit, consisting of a lipid bilayer surrounded by amphiphilic scaffold proteins, possesses intrinsically an elliptical shape. The temperature dependence of the curvature of the nanodiscs prepared with two different phospholipid types (DLPC and POPC) shows that it is the scaffold protein that determines the overall elliptical shape and that the nanodiscs become more circular with increasing temperature. Our data also show that the hydrophobic bilayer thickness is, to a large extent, dictated by the scaffolding protein and adjusted to minimize the hydrophobic mismatch between protein and phospholipid. Our conclusions result from a new comprehensive and molecular-based model of the nanodisc structure and the use of this to analyze the experimental scattering profile from nanodiscs. The model paves the way for future detailed structural studies of functional membrane proteins encapsulated in nanodiscs.

[1]  Jeffrey M. Skerker,et al.  Evolution, ecology and the engineered organism: lessons for synthetic biology , 2009, Genome Biology.

[2]  Feifei Gu,et al.  Structures of Discoidal High Density Lipoproteins , 2009, The Journal of Biological Chemistry.

[3]  D. Willbold,et al.  Integral membrane proteins in nanodiscs can be studied by solution NMR spectroscopy. , 2009, Journal of the American Chemical Society.

[4]  Zhang,et al.  Order and disorder in fully hydrated unoriented bilayers of gel-phase dipalmitoylphosphatidylcholine. , 1994, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[5]  Xavier Deupi,et al.  The effect of ligand efficacy on the formation and stability of a GPCR-G protein complex , 2009, Proceedings of the National Academy of Sciences.

[6]  Thomas W. Hamann,et al.  The nanodisc: a novel tool for membrane protein studies , 2009, Biological chemistry.

[7]  S. Sligar,et al.  Co-incorporation of heterologously expressed Arabidopsis cytochrome P450 and P450 reductase into soluble nanoscale lipid bilayers. , 2004, Archives of biochemistry and biophysics.

[8]  T. Huber,et al.  Rapid incorporation of functional rhodopsin into nanoscale apolipoprotein bound bilayer (NABB) particles. , 2008, Journal of molecular biology.

[9]  D. Bossev,et al.  Bending elasticity of saturated and monounsaturated phospholipid membranes studied by the neutron spin echo technique , 2009, Journal of physics. Condensed matter : an Institute of Physics journal.

[10]  Priscilla E. M. Purnick,et al.  The second wave of synthetic biology: from modules to systems , 2009, Nature Reviews Molecular Cell Biology.

[11]  Jeremy Pencer,et al.  Lipid bilayer structure determined by the simultaneous analysis of neutron and X-ray scattering data. , 2008, Biophysical journal.

[12]  Kirsten Jørgensen,et al.  Metabolon formation and metabolic channeling in the biosynthesis of plant natural products. , 2005, Current opinion in plant biology.

[13]  Klaus Schulten,et al.  Molecular dynamics simulations of discoidal bilayers assembled from truncated human lipoproteins. , 2005, Biophysical journal.

[14]  J. S. Pedersen,et al.  The aggregation behavior of zinc-free insulin studied by small-angle neutron scattering , 2004, European Biophysics Journal.

[15]  Lise Arleth,et al.  Small-angle scattering study of TAC8: A surfactant with cation complexing potential , 1997 .

[16]  Richard N. Zare,et al.  A monomeric G protein-coupled receptor isolated in a high-density lipoprotein particle efficiently activates its G protein , 2007, Proceedings of the National Academy of Sciences.

[17]  S. Sligar,et al.  Directed self-assembly of monodisperse phospholipid bilayer Nanodiscs with controlled size. , 2004, Journal of the American Chemical Society.

[18]  S. Sligar,et al.  Membrane protein assembly into Nanodiscs , 2010, FEBS letters.

[19]  S. Sligar,et al.  Functional reconstitution of Beta2-adrenergic receptors utilizing self-assembling Nanodisc technology. , 2006, BioTechniques.

[20]  C. Tanford Micelle shape and size , 1972 .

[21]  J. S. Pedersen,et al.  Scattering form factor of block copolymer micelles , 1996 .

[22]  R. Kwok Five hard truths for synthetic biology , 2010, Nature.

[23]  S. Sligar,et al.  Applications of phospholipid bilayer nanodiscs in the study of membranes and membrane proteins. , 2007, Biochemistry.

[24]  Sung Kuk Lee,et al.  Synthetic biology for biofuels: Building designer microbes from the scratch , 2010 .

[25]  O. Glatter,et al.  A new method for the evaluation of small‐angle scattering data , 1977 .

[26]  S. Sligar,et al.  Thermotropic phase transition in soluble nanoscale lipid bilayers. , 2005, The journal of physical chemistry. B.

[27]  A. Jonas Reconstitution of high-density lipoproteins. , 1986, Methods in enzymology.

[28]  M. Bloom,et al.  Mattress model of lipid-protein interactions in membranes. , 1984, Biophysical journal.

[29]  John F. Nagle,et al.  Structure of Fully Hydrated Fluid Phase Lipid Bilayers with Monounsaturated Chains , 2006, The Journal of Membrane Biology.

[30]  Mingshan Li,et al.  Nanodiscs separate chemoreceptor oligomeric states and reveal their signaling properties. , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[31]  R. Hjelm,et al.  Detailed structure of hairy mixed micelles formed by phosphatidylcholine and PEGylated phospholipids in aqueous media. , 2005, Langmuir : the ACS journal of surfaces and colloids.

[32]  S. Kaneshina,et al.  Thermotropic and barotropic phase transitions of dilauroylphosphatidylcholine bilayer. , 2008, Chemistry and physics of lipids.

[33]  S. Sligar,et al.  Recreation of the terminal events in physiological integrin activation , 2010, The Journal of cell biology.

[34]  Ying Li,et al.  Structural analysis of nanoscale self-assembled discoidal lipid bilayers by solid-state NMR spectroscopy. , 2006, Biophysical journal.

[35]  R. Strey Microemulsion microstructure and interfacial curvature , 1994 .

[36]  M. Nakano,et al.  Static and dynamic properties of phospholipid bilayer nanodiscs. , 2009, Journal of the American Chemical Society.

[37]  Dmitri I. Svergun,et al.  Accuracy of molecular mass determination of proteins in solution by small-angle X-ray scattering , 2007 .

[38]  Stephen G. Sligar,et al.  Self-Assembly of Discoidal Phospholipid Bilayer Nanoparticles with Membrane Scaffold Proteins , 2002 .

[39]  S. Hazen,et al.  Double Superhelix Model of High Density Lipoprotein* , 2009, The Journal of Biological Chemistry.

[40]  T. Sulchek,et al.  Atomic force microscopy differentiates discrete size distributions between membrane protein containing and empty nanolipoprotein particles. , 2009, Biochimica et biophysica acta.

[41]  Jarrod Clark,et al.  Mobility-shift analysis with microfluidics chips. , 2003, BioTechniques.

[42]  Patrik R. Jones,et al.  Metabolon formation in dhurrin biosynthesis. , 2008, Phytochemistry.

[43]  L. Finegold,et al.  Unusual phase properties of dilauryl phosphatidylcholine (C12PC) , 1990 .

[44]  A. Jonas,et al.  Micellar complexes of human apolipoprotein A-I with phosphatidylcholines and cholesterol prepared from cholate-lipid dispersions. , 1982, The Journal of biological chemistry.

[45]  Klaus Schulten,et al.  Disassembly of nanodiscs with cholate. , 2007, Nano letters.

[46]  B. Ninham,et al.  Theory of self-assembly of hydrocarbon amphiphiles into micelles and bilayers , 1976 .

[47]  S. Sligar,et al.  Self‐assembly of single integral membrane proteins into soluble nanoscale phospholipid bilayers , 2003, Protein science : a publication of the Protein Society.

[48]  S. Hansen Calculation of small-angle scattering profiles using Monte Carlo simulation , 1990 .

[49]  J. Gomez-Fernandez,et al.  The phase behavior of aqueous dispersions of unsaturated mixtures of diacylglycerols and phospholipids. , 1998, Biochimica et biophysica acta.

[50]  J. S. Pedersen Form factors of block copolymer micelles with spherical, ellipsoidal and cylindrical cores , 2000 .