title: Novel rare earth tungstoarsenate heteropolyoxometalates K11[Ln(AsW 11O 39) 2]·xH 2O (Ln = La, Nd, Sm) binding to bovine serum albumin: spectroscopic approach.
abstract: The rare earth salts of heteropoly have been widely applied in many fields. In this study, the biological activity of rare earth tungstoarsenate heteropolyoxometalates K11[Ln(AsW11O39)2]·xH2O (abbr. LnW11, Ln = La (x = 24), Nd (x = 17), and Sm (x = 19)) were investigated by spectroscopic methods including fluorescence spectroscopy and UV-vis absorption spectroscopy at different temperatures. In the mechanism discussion, it was proved that the fluorescence quenching of bovine serum albumin (BSA) by LnW11 is initiated by complex formation. The thermodynamic parameters suggested that the binding of LnW11 to BSA is spontaneous, and the mainly force is electrostatic interactions. Site marker competitive experiments demonstrated that LaW11 binds with high affinity to site I (subdomain IIA) of BSA; but SmW11 and NdW11 bind with affinity to both site I (subdomain IIA) and site II (subdomain IIIA) of BSA. The results of synchronous fluorescence spectrum indicate that the secondary structure of BSA molecules was changed in the presence of LnW11. In addition, the binding parameters, binding site number, and effect of metal ions on LnW11-BSA were also discussed.
authors.affiliation: Hubei Collaborative Innovation Center for Rare Metal Chemistry, Hubei Key Laboratory of Pollutant Analysis & Reuse Technology, Department of Chemistry, Hubei Normal University, Huangshi, 435002, People's Republic of China.
authors.forename: Shan
authors.initials: S
authors.lastname: Jiang
authors.forename: Li-Yang
authors.initials: LY
authors.lastname: Cheng
authors.forename: Ai-Min
authors.initials: AM
authors.lastname: Bai
authors.forename: Shu
authors.initials: S
authors.lastname: Zhou
authors.forename: Yan-Jun
authors.initials: YJ
authors.lastname: Hu
mesh_terms: D000818:Animals; D001149:Arsenates / Q000737:chemistry*; D002417:Cattle; D011485:Protein Binding; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D017973:Tungsten Compounds / Q000737:chemistry*
chemical_list: D001149:Arsenates; D017973:Tungsten Compounds; C021101:tungstic(VI) acid; C025657:arsenic acid