title: Synthesis and characterization of picket porphyrin receptors that bind phosphatidylglycerol, an anionic phospholipid found in bacterial membranes.
abstract: The lipid binding ability of four urea-picket porphyrins designed to bind to both the phosphate anion portion as well as the glycerol hydroxyl groups of phosphatidylglycerol (PG) has been investigated. Isothermal titration calorimetry (ITC) and (1)H NMR were used to determine the receptor's stoichiometry of binding, association constants, and both the enthalpy and entropy of binding with the PG anion. Spectral evidence shows that the phosphate anion portion of PG is hydrogen bonded to the urea groups of the receptors. This binding interaction orients the PG anion in the receptor pocket such that its glycerol hydroxyl groups can align with a third urea picket, and results are furnished that suggest this multifunctional interaction does occur. The structure of the entire picket was found to influence the enthalpy and entropy of lipid binding. The synthesis of tetrabutlyammonium phosphatidylglycerol (TBAPG), and a detailed spectral characterization of its headgroup, is also presented.
authors.affiliation: Department of Chemistry, Wichita State University, Wichita, Kansas 67260, USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: Alliband
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Meece
authors.forename: Champika
authors.initials: C
authors.lastname: Jayasinghe
authors.forename: Dennis H
authors.initials: DH
authors.lastname: Burns
mesh_terms: D000838:Anions / Q000737:chemistry*; D002151:Calorimetry; D008051:Lipid Bilayers / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010715:Phosphatidylglycerols / Q000138:chemical synthesis* / Q000737:chemistry*; D010743:Phospholipids / Q000008:administration & dosage* / Q000737:chemistry; D011166:Porphyrins / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D013816:Thermodynamics; D014508:Urea / Q000031:analogs & derivatives* / Q000737:chemistry*
chemical_list: D000838:Anions; D008051:Lipid Bilayers; D010715:Phosphatidylglycerols; D010743:Phospholipids; D011166:Porphyrins; D000644:Quaternary Ammonium Compounds; D014508:Urea