title: Carotenoid binding to proteins: Modeling pigment transport to lipid membranes.
abstract: Carotenoid pigments play numerous important physiological functions in human organism. Very special is a role of lutein and zeaxanthin in the retina of an eye and in particular in its central part, the macula lutea. In the retina, carotenoids can be directly present in the lipid phase of the membranes or remain bound to the protein-pigment complexes. In this work we address a problem of binding of carotenoids to proteins and possible role of such structures in pigment transport to lipid membranes. Interaction of three carotenoids, beta-carotene, lutein and zeaxanthin with two proteins: bovine serum albumin and glutathione S-transferase (GST) was investigated with application of molecular spectroscopy techniques: UV-Vis absorption, circular dichroism and Fourier transform infrared spectroscopy (FTIR). Interaction of pigment-protein complexes with model lipid bilayers formed with egg yolk phosphatidylcholine was investigated with application of FTIR, Raman imaging of liposomes and electrophysiological technique, in the planar lipid bilayer models. The results show that in all the cases of protein and pigment studied, carotenoids bind to protein and that the complexes formed can interact with membranes. This means that protein-carotenoid complexes are capable of playing physiological role in pigment transport to biomembranes.
authors.affiliation: Department of Biophysics, Institute of Physics, Maria Curie-Skłodowska University, 20-031 Lublin, Poland; Department of Biophysics, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, 20-031 Lublin, Poland.
authors.forename: Emilia
authors.initials: E
authors.lastname: Reszczynska
authors.affiliation: Department of Biophysics, Institute of Physics, Maria Curie-Skłodowska University, 20-031 Lublin, Poland.
authors.forename: Renata
authors.initials: R
authors.lastname: Welc
authors.affiliation: Department of Biophysics, Institute of Physics, Maria Curie-Skłodowska University, 20-031 Lublin, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Grudzinski
authors.affiliation: Department of Biophysics, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, 20-031 Lublin, Poland.
authors.forename: Kazimierz
authors.initials: K
authors.lastname: Trebacz
authors.affiliation: Department of Biophysics, Institute of Physics, Maria Curie-Skłodowska University, 20-031 Lublin, Poland. Electronic address: wieslaw.gruszecki@umcs.pl.
authors.forename: Wieslaw I
authors.initials: WI
authors.lastname: Gruszecki
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D002417:Cattle; D005982:Glutathione Transferase / Q000737:chemistry*; D006801:Humans; D014975:Lutein / Q000737:chemistry*; D032305:Lycium / Q000737:chemistry*; D008563:Membrane Lipids / Q000737:chemistry*; D008567:Membranes, Artificial; D008956:Models, Chemical; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D018724:Spinacia oleracea / Q000737:chemistry*; D065146:Zeaxanthins / Q000737:chemistry*
chemical_list: D008563:Membrane Lipids; D008567:Membranes, Artificial; D065146:Zeaxanthins; D012710:Serum Albumin, Bovine; D005982:Glutathione Transferase; D014975:Lutein
keywords: Carotenoids; Carotenoid–protein complexes; Lutein; Macula; Retina; Xanthophylls; Zeaxanthin