Series of Novel Rare Earth Molybdotungstosilicate Heteropolyoxometalates Binding to Bovine Serum Albumin: Spectroscopic Approach

• Published in: Biological trace element research 2010-07, Vol.136 (1), p.8-17
• Main Authors: Hu, Yan-Jun, Ou-Yang, Yu, Bai, Ai-Min, Zhao, Ru-Ming, Liu, Yi
• Format: Article
• Language: English
• Subjects: Biochemistry; Biomedical and Life Sciences; Biotechnology; Blood tests; Cattle; Chemical compounds; Energy transfer; Fluorescence; Life Sciences; Metals, Rare Earth - chemistry; Molybdenum - chemistry; Nutrition; Oncology; Protein Binding; Serum Albumin, Bovine - chemistry; Silicates - chemistry; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Spectrum analysis; Thermodynamics; Tungsten Compounds - chemistry
• ISSN: 0163-4984; 1559-0720
• DOI: 10.1007/s12011-009-8521-8

Heteropolyoxometalate complexes have been widely applied in many fields. In this paper, the interaction between a series of novel rare earth molybdotungstosilicate heteropolyoxometalates, K₁₀H₃[Ln(SiMo₆W₅O₃₉)₂]·xH₂O (abbr. LnW₅, Ln = Pr (x = 30), Gd (x = 29), Dy (x = 28), and Yb (x = 31)), and bovine serum albumin (BSA) was investigated by spectroscopic approach under the physiological conditions. In the mechanism discussion, it was proved that the fluorescence quenching of BSA by LnW₅ is a result of the formation of LnW₅-BSA complex. Fluorescence quenching constants were determined using the Stern-Volmer equation to provide a measure of the binding affinity between LnW₅ and BSA. The binding affinity ranked in the order GdW₅ > DyW₅ > PrW₅ > YbW₅. The results of thermodynamic parameters ΔG, ΔH, and ΔS at different temperatures indicate that van der Waals interactions and hydrogen bonds play a major role for LnW₅-BSA association. Furthermore, the distance r between donor (BSA) and acceptor (LnW₅) was obtained according to fluorescence resonance energy transfer.