title: Iron Ion and Iron Hydroxide Adsorption to Charge-Neutral Phosphatidylcholine Templates.
abstract: 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 μM FeCl3 solutions at physiological levels of KCl (100 mM). At 40 μM of Fe(III) as many as ∼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.
authors.affiliation: Division of Materials Sciences and Engineering, Ames Laboratory, USDOE , Ames, Iowa 50011, United States.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Wang
authors.affiliation: Ames Laboratory and Department of Materials Science and Engineering, Iowa State University , Ames, Iowa 50011, United States.
authors.forename: Honghu
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Ames Laboratory and Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University , Ames, Iowa 50011, United States.
authors.forename: Shuren
authors.initials: S
authors.lastname: Feng
authors.affiliation: Division of Materials Sciences and Engineering, Ames Laboratory, USDOE , Ames, Iowa 50011, United States.
authors.forename: Josue
authors.initials: J
authors.lastname: San Emeterio
authors.affiliation: Ames Laboratory and Department of Chemical and Biological Engineering, Iowa State University , Ames, Iowa 50011, United States.
authors.forename: Surya
authors.initials: S
authors.lastname: Mallapragada
authors.affiliation: Ames Laboratory and Department of Physics and Astronomy, Iowa State University , Ames, Iowa 50011, United States.
authors.forename: David
authors.initials: D
authors.lastname: Vaknin
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D000327:Adsorption; D002712:Chlorides / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry; D010713:Phosphatidylcholines / Q000737:chemistry; D011189:Potassium Chloride / Q000737:chemistry
chemical_list: D002712:Chlorides; D005290:Ferric Compounds; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D015060:1,2-Dipalmitoylphosphatidylcholine; C021024:ferric hydroxide; D011189:Potassium Chloride; D007501:Iron; C024555:ferric chloride