title: A comparative study on the binding of single and double chain surfactant-cobalt(III) complexes with bovine serum albumin.
abstract: The comparative binding effect of single and double aliphatic chain containing surfactant-cobalt(III) complexes cis-[Co(bpy)2(DA)2](ClO4)3·2H2O (1), cis-[Co(bpy)2(DA)Cl](ClO4)2·2H2O (2), cis-[Co(phen)2(CA)2](ClO4)3·2H2O (3), and cis-[Co(phen)2(CA)Cl](ClO4)2·2H2O (4) with bovine serum albumin (BSA) under physiological condition was analyzed by steady state, time resolved fluorescence, synchronous, three-dimensional fluorescence, UV-Visible absorption and circular dichroism spectroscopic techniques. The results show that these complexes cause the fluorescence quenching of BSA through a static mechanism. The binding constants (Kb) and the number of binding sites were calculated and binding constant values are found in the range of 10(4)-10(5) M(-1). The results indicate that compared to single chain complex, double chain surfactant-cobalt(III) complex interacts strongly with BSA. Also the sign of thermodynamic parameters (ΔG°, ΔH°, and ΔS°) indicate that all the complexes interact with BSA through hydrophobic force. The binding distance (r) between complexes and BSA was calculated using Förster non-radiation energy transfer theory and found to be less than 7 nm. The results of synchronous, three dimensional fluorescence and circular dichroism spectroscopic methods indicate that the double chain surfactant-cobalt(III) complexes changed the conformation of the protein considerably than the respective single chain surfactant-cobalt(III) complexes. Antimicrobial studies of the complexes showed good activities against pathogenic microorganisms.
authors.affiliation: School of Chemistry, Bharathidasan University, Tiruchirapalli 620 024, Tamil Nadu, India.
authors.forename: G
authors.initials: G
authors.lastname: Vignesh
authors.forename: K
authors.initials: K
authors.lastname: Sugumar
authors.forename: S
authors.initials: S
authors.lastname: Arunachalam
authors.forename: S
authors.initials: S
authors.lastname: Vignesh
authors.forename: R
authors.initials: R
authors.lastname: Arthur James
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D001665:Binding Sites; D002417:Cattle; D002942:Circular Dichroism; D003035:Cobalt / Q000378:metabolism* / Q000494:pharmacology; D056831:Coordination Complexes / Q000378:metabolism / Q000494:pharmacology; D004735:Energy Transfer / Q000187:drug effects; D005658:Fungi / Q000187:drug effects; D008823:Micelles; D008826:Microbial Sensitivity Tests; D011485:Protein Binding / Q000187:drug effects; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013501:Surface-Active Agents / Q000378:metabolism*; D013816:Thermodynamics; D014364:Tryptophan / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism
chemical_list: D000890:Anti-Infective Agents; D056831:Coordination Complexes; D008823:Micelles; D013501:Surface-Active Agents; D012710:Serum Albumin, Bovine; D003035:Cobalt; D014443:Tyrosine; D014364:Tryptophan
keywords: Antimicrobial activities; Binding parameters; Bovine serum albumin; Surfactant–cobalt(III) complexes