title: Label-free chiral detection of melittin binding to a membrane.
abstract: The study presented here describes an innovative approach for the detection of surface-confined proteins using chiral second harmonic generation (C-SHG). A unique optical geometry has been employed which allows for the separation of the chiral and achiral nonlinear response. By utilizing this optical arrangement, the detection of chirality originating from melittin adsorbed to a planar supported lipid bilayer has been performed for the first time by C-SHG. Melittin binding to the membrane was monitored as a function of bulk concentration through detection of the C-SHG signal. Analysis of the C-SHG adsorption isotherms reveals Frumkin adsorption behavior with a positive interaction energy. The binding constant (Ka) obtained was determined to be (8.3 +/- 1.0) x 105 M-1. The results of these studies have far-reaching implication in the use of C-SHG for the label-free detection of protein association to surfaces and in the analysis of protein interfacial phenomena.
authors.affiliation: Department of Chemistry, University of Utah, 315 South, 1400 East, Room 2020, Salt Lake City, Utah 84112, USA.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Kriech
authors.forename: John C
authors.initials: JC
authors.lastname: Conboy
mesh_terms: D000595:Amino Acid Sequence; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism*; D008555:Melitten / Q000737:chemistry / Q000378:metabolism*; D008566:Membranes / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D010713:Phosphatidylcholines / Q000737:chemistry / Q000378:metabolism*; D017785:Photons; D011485:Protein Binding; D017433:Protein Structure, Secondary; D013057:Spectrum Analysis / Q000379:methods; D013237:Stereoisomerism
chemical_list: D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D008555:Melitten; C028694:1-palmitoyl-2-oleoylphosphatidylcholine