Stacked 2D Crystalline Sheets of the Membrane-Protein Bacteriorhodopsin: A Specular and Diffuse Reflectivity Study

We report a specular and diffuse x-ray reflectivity study of a model multilayer membraneprotein system. Native membranes containing two-dimensional crystals of the membrane-protein bacteriorhodopsin were fused into giant s10 mmd single-crystalline patches and stacked to form perfect orientationally aligned multilayers. The diffuse scattering indicates a conformal buckling of the membranes on length scales of a few hundred angstroms. Analysis of the truncation rods allows us to elucidate the intermembrane correlations of the proteins at different hydration levels of the multilayer. [S0031-9007(98)07168-3]