Journal of the American Chemical Society, Vol.132, No.30, 10383-10390, 2010
Protein and Small Molecule Recognition Properties of Deep Cavitands in a Supported Lipid Membrane Determined by Calcination-Enhanced SPR Spectroscopy
This paper details the incorporation of a water-soluble deep cavitand into a membrane bilayer assembled onto a nanoglassified surface for study of molecular recognition in a membrane-mimicking setting. The cavitand retains its host properties, and real-time analysis of the host:guest properties of the membrane: cavitand complex via surface plasmon resonance and fluorescence microscopy is described. The host shows selectivity for choline-derived substrates, and no competitive incorporation of substrate is observed in the membrane bilayer. A variety of trimethylammonium-derived substrates are suitable guests, displaying varied binding affinities in a millimolar range. The membrane:cavitand:guest complexes can be subsequently used to capture NeutrAvidin protein at the membrane surface if a biotin-derived guest molecule is used. The surface coverage of NeutrAvidin is affected by the spacer used to derivatize the biotin. Increased distance from the bilayer allows a higher concentration of protein to be immobilized, suggesting a diminishing detrimental steric effect when the binding event is shifted away from the surface.