Molecular organization of the human serotonin transporter at the air/water interface

AbstractThe serotonin transporter (SERT) is the target of several important antidepressant and psychostimulant drugs. It has been shown that under defined conditions, the transporter spread at the air/water interface was able to bind its specific ligands. In this paper, the interfacial organization of the protein has been assessed from dynamic surface pressure and ellipsometric measurements. For areas comprising between 10 400 and 7100 Å2/molecule, ellipsometric measurements reveal an important change in the thickness of the SERT film. This change was attributed to the reorientation of the transporter molecules from a horizontal to their natural predictive transmembrane orientation. The thickness of the SERT film at 7100 Å2/molecule was found to be approximately equal to 84 Å and coincided well with the theoretical value estimated from the calculations based on the dimensions of α-helices containing membrane proteins. These data suggest that the three-dimensional arrangement of the SERT may be represented as a box with lengths dz=83–85 Å and dy or dx=41–47 Å

Inhibition of surface induced coagulation by preadsorption of albumin-heparin conjugates

Surface coatings of the albumin-heparin conjugates were developed to improve the blood compatibility of polymeric materials. Glass, PVC, Biomer and cellulose acetate were coated with albumin-heparin conjugate and its adsorption and desorption behavior on glass in particular was studied using 3H and 51Cr radiolabeled conjugates. Precoated materials showed a significant prolongation of the Lee-White clotting time as compared with noncoated ones. It was demonstrated that the prolonged clotting time for pretreated glass was due to surface bound conjugate. Prolonged recalcification times of plasma exposed to glass, Biomer, and PVC were obtained using albumin-heparin conjugate precoated surfaces. Albumin-heparin conjugates with high affinity for antithrombin III gave more prolonged clotting times as low affinity conjugates when used as coatings for glass. This indicates that the behaviour of heparin in preadsorbed conjugates resembles that of heparin in solution

Specific interaction of lectins with liposomes and monolayers bearing neoglycolipids

The interaction of three lectins (wheat germ, Ulex europaeus I, and Lotus tetragonolobus agglutinins: WGA, UEA-I and LTA) with either N-acetyl--glucosamine or -fucose neoglycolipids incorporated into phospholipid monolayers and liposome bilayers was studied at the air/water interface and in bulk solution.http://www.sciencedirect.com/science/article/B6T2N-497HFTC-1/1/22d2980a499b2c91ce83c2d9a6cfaa8