Annexin A1 interaction with a zwitterionic phospholipid monolayer: a fluorescence microscopy study.
(2004)
Journal - Langmuir : the ACS journal of surfaces and colloids (United States )
Abstract :
We present the results of a fluorescence microscopy study of the interaction of annexin A1 with dipalmitoylphosphatidylcholine (DPPC) monolayers as a function of the lipid monolayer phase and the pH of the aqueous subphase. We show that annexin A1-DPPC interaction depends strongly on the domain structure of the DPPC monolayer and only weakly on the subphase pH. Annexin A1 is found to be line active, with preferential adsorption at phase boundaries. Also, annexin A1 is found to form networks in the presence of a domain structure in the monolayer. Our results point toward an important contribution of the unique N-terminal domain to the organization of the protein at the interface.
| ISSN : | 0743-7463 |
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| Mesh Heading : | 1,2-Dipalmitoylphosphatidylcholine Annexin A1 Hydrogen-Ion Concentration Microscopy, Fluorescence |
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| Mesh Heading Relevant : | chemistry chemistry |
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Molecular dynamics simulations of a pulmonary surfactant protein B peptide in a lipid monolayer.
(2003)
Journal - Biophysical journal (United States )
Abstract :
Pulmonary surfactant is a complex mixture of lipids and proteins that lines the air/liquid interface of the alveolar hypophase and confers mechanical stability to the alveoli during the breathing process. The desire to formulate synthetic mixtures for low-cost prophylactic and therapeutic applications has motivated the study of the specific roles and interactions of the different components. All-atom molecular dynamics simulations were carried out on a model system composed of a monolayer of palmitic acid (PA) and a surfactant protein B peptide, SP-B(1-25). A detailed structural characterization as a function of the lipid monolayer specific area revealed that the peptide remains inserted in the monolayer up to values of specific area corresponding to an untilted condensed phase of the the pure palmitic acid monolayer. The system remains stable by altering the conformational order of both the anionic lipid monolayer and the peptide secondary structure. Two elements appear to be key for the constitution of this phase: an electrostatic interaction between the cationic peptide residues with the anionic headgroups, and an exclusion of the aromatic residues on the hydrophobic end of the peptide from the hydrophilic and aqueous regions.
| ISSN : | 0006-3495 |
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| Mesh Heading : | Biomimetics Computer Simulation Crystallography Lipids Macromolecular Substances Motion Palmitic Acid Protein Binding Protein Conformation Protein Structure, Secondary Protein Structure, Tertiary Pulmonary Surfactant-Associated Protein B Solutions Static Electricity Surface Properties methods chemistry |
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| Mesh Heading Relevant : | Membranes, Artificial Models, Molecular methods chemistry chemistry chemistry |
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Molecular Dynamics Simulations of a Pulmonary Surfactant Protein B Peptide in a Lipid Monolayer
(2003)
Journal - Biophysical Journal
Abstract :
Pulmonary surfactant is a complex mixture of lipids and proteins that lines the air/liquid interface of the alveolar hypophase and confers mechanical stability to the alveoli during the breathing process. The desire to formulate synthetic mixtures for low-cost prophylactic and therapeutic applications has motivated the study of the specific roles and interactions of the different components. All-atom molecular dynamics simulations were carried out on a model system composed of a monolayer of palmitic acid (PA) and a surfactant protein B peptide, SP-B1–25. A detailed structural characterization as a function of the lipid monolayer specific area revealed that the peptide remains inserted in the monolayer up to values of specific area corresponding to an untilted condensed phase of the the pure palmitic acid monolayer. The system remains stable by altering the conformational order of both the anionic lipid monolayer and the peptide secondary structure. Two elements appear to be key for the constitution of this phase: an electrostatic interaction between the cationic peptide residues with the anionic headgroups, and an exclusion of the aromatic residues on the hydrophobic end of the peptide from the hydrophilic and aqueous regions.