title: Cooperative binding at lipid bilayer membrane surfaces.
abstract: The binding of copper(II) ions to membrane-bound synthetic receptors has been investigated. Complexation fitted a 4:1 receptor:copper(II) model, and the observed binding constants are significantly enhanced at the membrane relative to solution; these effects can be explained by the lower polarity of the membrane-water interface and the concentrating effect of the membrane, with no observed contribution from receptor preorganization. The stoichiometry of the complex formed is very sensitive to the concentration of the receptor in the membrane, and at low concentrations, binding is reduced relative to solution controls. This implies that by increasing or decreasing the number of receptors in their membranes, cells can finely tune biological responses such as chemotaxis that depend on the size of the receptor-ligand clusters formed.
authors.affiliation: Centre for Chemical Biology, Krebs Institute for Biomolecular Science, Department of Chemistry, The University of Sheffield, Sheffield, S3 7HF, U.K.
authors.forename: Emma L
authors.initials: EL
authors.lastname: Doyle
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Hunter
authors.forename: Helen C
authors.initials: HC
authors.lastname: Phillips
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Webb
authors.forename: Nicholas H
authors.initials: NH
authors.lastname: Williams
mesh_terms: D002784:Cholesterol / Q000737:chemistry; D003300:Copper / Q000737:chemistry / Q000378:metabolism*; D003619:Dansyl Compounds / Q000737:chemistry; D005029:Ethylenediamines / Q000737:chemistry; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000378:metabolism*; D014867:Water / Q000737:chemistry / Q000378:metabolism
chemical_list: D003619:Dansyl Compounds; D005029:Ethylenediamines; D008051:Lipid Bilayers; D011956:Receptors, Cell Surface; D014867:Water; C032377:dansylethylenediamine; D003300:Copper; D002784:Cholesterol