title: NMR screening of new carbocyanine dyes as ligands for affinity chromatography.
abstract: Four new carbocyanines containing symmetric and asymmetric heterocyclic moieties and N-carboxyalkyl groups have been synthesized and characterized. The binding mechanism established between these cyanines and several proteins was evaluated using saturation transfer difference (STD) NMR. The results obtained for the different dyes revealed a specific interaction to the standard proteins lysozyme, α-chymotrypsin, ribonuclease (RNase), bovine serum albumin (BSA), and gamma globulin. For instance, the two un-substituted symmetrical dyes (cyanines 1 and 3) interacted preferentially through its benzopyrrole and dibenzopyrrole units with lysozyme, α-chymotrypsin, and RNase, whereas the symmetric disulfocyanine dye (cyanine 2) bound BSA and gamma globulin through its carboxyalkyl chains. On the other hand, the asymmetric dye (cyanine 4) interacts with lysozyme and α-chymotrypsin through benzothiazole moiety and with RNase through dibenzopyrrole unit. Thus, STD-NMR technique was successfully used to screen cyanine-protein interactions and determine potential binding sites of the cyanines for posterior use as ligands in affinity chromatography.
authors.affiliation: CICS-UBI-Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Av. Infante D. Henrique, 6200-506, Covilhã, Portugal.
authors.forename: Carla
authors.initials: C
authors.lastname: Cruz
authors.forename: Renato E F
authors.initials: RE
authors.lastname: Boto
authors.forename: Anna K
authors.initials: AK
authors.lastname: Drzazga
authors.forename: Paulo
authors.initials: P
authors.lastname: Almeida
authors.forename: João A
authors.initials: JA
authors.lastname: Queiroz
mesh_terms: D000818:Animals; D052160:Benzothiazoles / Q000737:chemistry; D001665:Binding Sites; D002232:Carbocyanines / Q000737:chemistry*; D002417:Cattle; D002846:Chromatography, Affinity; D005456:Fluorescent Dyes / Q000737:chemistry*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D009113:Muramidase / Q000737:chemistry; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry*
chemical_list: D052160:Benzothiazoles; D002232:Carbocyanines; D005456:Fluorescent Dyes; D008024:Ligands; D011506:Proteins; D012710:Serum Albumin, Bovine; D009113:Muramidase; C005465:benzothiazole
keywords: NMR; cyanine ligands; molecular interactions; proteins