title: Chiral recognition of bilirubin and biliverdin in liposomes and micelles.
abstract: The structural formula of biologically important chiral pigments bilirubin and biliverdin differs only by one double bond. We showed that this results in dissimilar interactions with two models of membranes: cationic liposomes composed of 3β-[N-(N',N'-dimethylaminoethane)-carbamoyl]cholesterol and zwitterionic micelles from 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS). While the liposomes recognized the P-form of bilirubin, the micelles recognized its M-form. Both recognized the P-form of biliverdin. Our study also comprised ternary systems consisting of the pigments, model membranes and serum albumin (human and bovine). Bilirubin preferentially interacted with the albumins even in the presence of the liposomes. On the other hand, biliverdin preferred the liposomes. Remarkably, the presence of CHAPS completely changed the biliverdin binding to the protein. Because our study was oriented on different chiral interactions, a chiroptical method of electronic circular dichroism was chosen as the principal method to study our systems. As complementary methods, UV-vis absorption and fluorescence emission were used.
authors.affiliation: Department of Analytical Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic.
authors.forename: Pavlína
authors.initials: P
authors.lastname: Novotná
authors.affiliation: Department of Analytical Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic.
authors.forename: František
authors.initials: F
authors.lastname: Králík
authors.affiliation: Department of Physics and Measurements, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic. Electronic address: Marie.Urbanova@vscht.cz.
authors.forename: Marie
authors.initials: M
authors.lastname: Urbanová
mesh_terms: D000818:Animals; D001664:Biliverdine / Q000737:chemistry* / Q000378:metabolism*; D001667:Binding, Competitive; D002417:Cattle; D002784:Cholesterol / Q000031:analogs & derivatives / Q000378:metabolism; D002793:Cholic Acids / Q000378:metabolism; D006801:Humans; D008823:Micelles; D008958:Models, Molecular; D008968:Molecular Conformation; D012710:Serum Albumin, Bovine / Q000378:metabolism; D013237:Stereoisomerism; D053835:Unilamellar Liposomes / Q000737:chemistry / Q000378:metabolism*
chemical_list: D002793:Cholic Acids; D008823:Micelles; D053835:Unilamellar Liposomes; C070648:3-(N-(N',N'-dimethylaminoethane)carbamoyl)cholesterol; D012710:Serum Albumin, Bovine; D002784:Cholesterol; D001664:Biliverdine; C028213:3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate
keywords: Bilirubin; Biliverdin; Electronic circular dichroism; Liposome; Micelle; Serum albumin