Kell Mortensen - Elliptical Structure of Phospholipid Bilayer Nanodiscs Encapsulated by Scaffold Proteins: Casting the Roles of the Lipids and the Protein

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      Publication Details (including relevant citation   information):

      J. Am. Chem. Soc., 2010, 132 (39), pp 13713–13722

      Publication Date (Web): September 9, 2010. Copyright © 2010   American Chemical Society


      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.

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