Novel Rare Earth Tungstoarsenate Heteropolyoxometalates K11[Ln(AsW11O39)2]·xH2O (Ln = La, Nd, Sm) Binding to Bovine Serum Albumin: Spectroscopic Approach

• Published in: Biological trace element research Vol. 163; no. 1-2; pp. 275 - 282
• Main Authors: Jiang, Shan, Cheng, Li-Yang, Bai, Ai-Min, Zhou, Shu, Hu, Yan-Jun
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.02.2015
• Subjects: Biochemistry; Biomedical and Life Sciences; Biotechnology; Life Sciences; Nutrition; Oncology; Bovine serum albumin; Rare earth; Tungstoarsenate heteropolyoxometalate; Biological activity; Spectroscopic method
• ISSN: 0163-4984; 1559-0720
• DOI: 10.1007/s12011-014-0183-5

The rare earth salts of heteropoly have been widely applied in many fields. In this study, the biological activity of rare earth tungstoarsenate heteropolyoxometalates K 11 [Ln(AsW 11 O 39 ) 2 ]·xH 2 O (abbr. LnW 11 , 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 LnW 11 is initiated by complex formation. The thermodynamic parameters suggested that the binding of LnW 11 to BSA is spontaneous, and the mainly force is electrostatic interactions. Site marker competitive experiments demonstrated that LaW 11 binds with high affinity to site I (subdomain IIA) of BSA; but SmW 11 and NdW 11 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 LnW 11 . In addition, the binding parameters, binding site number, and effect of metal ions on LnW 11 –BSA were also discussed.