Chemical Laboratory, CLRI (CSIR), Adyar, Chennai 600020, India.
J Phys Chem B. 2010 Jun 24;114(24):8067-75. doi: 10.1021/jp100896b.
Langmuir films of pure fibrinogen (Fg) and Fg spread at the air/buffer interface and subphase containing electrolytes, NaCl, KCl, CaCl(2), and ZnCl(2), have been analyzed to understand the role of the surface/interface in mediating the organization of the protein eventually to fibrils. These films have been characterized by the surface pressure and surface potential-molecular area ((pi-A) and (DeltaV-A)) isotherms and Brewster angle microscopy (BAM). The Langmuir-Blodgett (LB) films of the protein transferred to the solid substrates have been characterized by scanning electron microscopy (SEM) and circular dichroism (CD). Our results suggest that fibrils are formed during organization at air/solution interface and also in LB films. The rate of formation of the fibril is the maximum for Fg with ZnCl(2). Adsorption of Fg to surfaces coated with a neutral lipid, dimyristoylphosphatidylcholine (DMPC), and a cationic lipid, dioctadecyldimethylammonium bromide (DOMA), from a range of solution concentrations has been studied using a quartz crystal microbalance (QCM). The work of adhesion of the protein on the solid surface shows fibril formation and positive adhesion for Fg in the presence of electrolytes. SEM results show that the adherent protein exhibits the widely reported nodulelike structure in the presence of CaCl(2) and ZnCl(2). These results provide definite evidence that specifically designed surfaces can promote adhesion of Fg and also activate fibril formation even in the absence of thrombin.
已对纯纤维蛋白原（Fg）的 Langmuir 膜以及在含有电解质（NaCl、KCl、CaCl2 和 ZnCl2）的空气/缓冲液界面和亚相上展开的 Fg 膜进行了分析，以便了解表面/界面在介导蛋白质最终形成纤维的过程中的作用。这些膜的表面压力和表面电势-分子面积（(pi-A) 和 (DeltaV-A) 等温线和偏光显微镜（BAM）进行了表征。通过扫描电子显微镜（SEM）和圆二色性（CD）对转移到固体基底上的蛋白质 Langmuir-Blodgett（LB）膜进行了表征。我们的结果表明，纤维原纤维在空气/溶液界面的组织过程中和在 LB 膜中形成。在存在 ZnCl2 的情况下，纤维原纤维的形成速度最快。已使用石英晶体微天平（QCM）研究了一系列溶液浓度下，中性脂质二肉豆蔻酰磷脂酰胆碱（DMPC）和阳离子脂质二油酰基二甲基氯化铵（DOMA）涂覆的表面上纤维蛋白原的吸附。蛋白质在固体表面上的粘附功表明，在存在电解质的情况下，纤维蛋白原形成纤维并具有正粘附性。SEM 结果表明，在存在 CaCl2 和 ZnCl2 的情况下，附着的蛋白质呈现出广泛报道的结节状结构。这些结果提供了明确的证据，表明经过专门设计的表面可以促进纤维蛋白原的粘附，并且即使在没有凝血酶的情况下也可以激活纤维原纤维的形成。
