|Title||Iron Ion and Iron Hydroxide Adsorption to Charge-Neutral Phosphatidylcholine Templates|
|Publication Type||Journal Article|
|Year of Publication||2016|
|Authors||Wang, WJ, Zhang, HH, Feng, SR, San Emeterio, J, Mallapragada, S, Vaknin, D|
|Type of Article||Article|
|Keywords||air-water-interface, air/water interface, bacterial protein, binding, chemistry, grazing-incidence diffraction, langmuir monolayers, Materials Science, membrane surfaces, phase-behavior, phospholipid monolayers, x-ray reflectivity|
Surface-sensitive X-ray scattering and spectroscopy techniques reveal significant adsorption of iron ions and iron-hydroxide (Fe(III)) complexes to a charge-neutral zwitterionic template of phosphatidylcholine (PC). The PC template is formed by a Langmuir monolayer of dipalmitoyl-PC (DPPC) that is spread on the surface of 2 to 40 mu M FeCl3 solutions at physiological levels of KCl (100 mM). At 40 mu M of Fe(III) as many as similar to 3 iron atoms are associated with each PC group. Grazing incidence X-ray diffraction measurements indicate a significant disruption in the in-plane ordering of DPPC molecules upon iron adsorption. The binding of iron-hydroxide complexes to a neutral PC surface is yet another example of nonelectrostatic, presumably covalent bonding to a charge-neutral organic template. The strong binding and the disruption of in-plane lipid structure has biological implications on the integrity of PC-derived lipid membranes, including those based on sphingomyelin.
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