Incorporation of Blood-Clotting Proteins into Phospholipid Langmuir Monolayers: A Fluorescence Microscopy Study

• Published in: Journal of colloid and interface science Vol. 239; no. 1; pp. 139 - 144
• Main Authors: Brancato, Sam, Serfis, Alexa
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01-07-2001; Elsevier
• Subjects: Biological and medical sciences; blood-clotting protein; Chemistry; Exact sciences and technology; fluorescence microscopy; Fundamental and applied biological sciences. Psychology; Gas-liquid interface and liquid-liquid interface; General and physical chemistry; Molecular biophysics; monolayer; phospholipid; Surface physical chemistry; Surface properties. Adsorption; monolayer; blood-clotting protein; phospholipid; fluorescence microscopy; Monolayer; Phospholipid; Lipids; Fibroprotein; Air water interface; Experimental study; Langmuir layer; Factor VII; Globular protein; Intermolecular interaction; Adsorption; Fibrinogen; Gas solid interface; Phosphatidylcholine; Fluorescence microscopy
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1006/jcis.2001.7557

Phospholipid monolayers adsorbed at an air–water interface are model cell membranes and have been used in this work to study interactions with blood-clotting proteins. Factor I (non–membrane binding) was used as a control protein, and its association with L-α-dipalmitoylphosphatidylcholine Langmuir monolayers was compared to factor VII, a membrane-binding protein. Fluorescence micrographs indicated that factor I penetration of the lipid monolayers in the phase transition region occurred extensively, causing condensation of the lipid film. The association of factor I with phospholipid monolayers was deemed nonspecific. Factor VII was shown to associate with the periphery of lipid domains in the absence of calcium ions, causing flattening of domain edges. In the presence of calcium, factor VII induced expansion of the lipid monolayer. This effect is a specific interaction attributed to exposure of hydrophobic residues upon calcium binding, followed by protein association with lipid hydrocarbon chains.