Chem. J. Chinese Universities ›› 2010, Vol. 31 ›› Issue (5): 911.

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Interaction of Psoralen or Isopsoralen with Human Immunoglobulin

HE Wen-Ying1*, YAO Xiao-Jun2, HU Zhi-De2, CHEN Guang-Ying3   

  1. 1. Department of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158, China;
    2. Department of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China;
    3. Hainan Provincial Key Lab of Tropical Pharmaceutical Herb Chemistry, Haikou 571158, China
  • Received:2009-09-21 Online:2010-05-10 Published:2010-05-10
  • Contact: HE Wen-Ying. E-mail: hwylsl-0706@163.com
  • Supported by:

    国家自然科学基金(批准号: 20862005)资助.

Abstract:

The active components of plant herbs possessed analogical isomeride structure(psoralen and isopsoralen) were selected as research targets. A combination of intrinsic fluorescence, UV-Vis spectroscopy, FTIR and the molecular modeling technique has been used to characterize the binding between both coumarins and human gammagobulin(HG). The results from fluorescence spectroscopy indicated that the two drugs could interact with the protein strongly(binding constants between 0.251×104—3.503×104). The two drugs indicated the same static quenching mechanism for HG. The binding parameters for the different drug-protein systems are different under different temperatures(298, 308 and 318 K), and the binding modes were also different. The values of r are lower than 7 nm after interaction between the protein tryptophan residue and the bound psoralen or isopsoralen molecules(3.65 and 4.21 nm, respectively), which indicated the efficiency of energy transfer according to Förster theory. The secondary structure compositions of the globulin and the drugs complexs were estimated by qualitative and quantitative analysis from synchronous fluorescence spectra and FTIR experimental data.The molecular model studies revealed the analogial binding locations and identical binding mode for drug-HG systems. The similarities and differences between the results of these experiments may be related to the two isomers of the structure of psoralen and isopsoralen.

Key words: Psoralen; Isopsoralen; Human gammagobulin; Interaction

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