Association Mechanism of S-Dinitrophenyl Glutathione with Two Glutathione Peroxidase Mimics: 2, 2′-Ditelluro- and 2, 2′-Diseleno-bridged β-cyclodextrins

Molecules

Ya-Qiong Hao¹  Xing-Chen Liu¹  Jun-Qiu Liu¹ 

[1] State Key Laboratory for Supramolecular Structure and Materials, Jilin University, Changchun, 130012, P. R. China; E-mails

关键词: 2;    2′-Ditelluro-bridged β-cyclodextrins;    2;    2′-Diseleno-bridged β-cyclodextrins;    Association mechanism;    MM2 modeling;    NMR spectroscopy;   

DOI  :  10.3390/molecules14030904

来源: mdpi

【 摘 要 】

Complex formation of the glutathione peroxidase mimics 2,2′-ditelluro-bridged β-cyclodextrin (1) and 2,2′-diseleno-bridged β-cyclodextrin (2), with S-substituted dinitrophenyl glutathione (3) were determined by ultraviolet-visible (UV-Vis) absorption spectroscopy in phosphate buffer (pH 7.4) and ¹H-NMR spectroscopy. Molecular mechanics (MM2) modeling calculations were used to deduce a three-dimensional model for each complex. The dinitrophenyl (DNP) group of 3 appears to penetrate the cavity of β-cyclodextrin (β-CD) or 1, but it is located between the two secondary rims of 2. The complexes’ stability constants (K_s) from 19 to 37 °C, Gibbs free energy changes (ΔG°), ΔH° and TΔS° for 1:1 complexes of β-CD,1 and 2 with ligand 3 as obtained from UV-Vis spectra were compared. The binding of 3 by the three cyclodextrin hosts generally decreased in the order of 1>2>β-CD. The binding ability of 3 by β-CD, 1 and 2 was discussed with regard to the size/shape-fit concept, the induced-fit interaction, and the cooperative interaction of the dual hydrophobic cavities. The binding ability of 1>2 indicated that the length of linkage between two cyclodextrin units plays a crucial role in the interaction with 3.

【 授权许可】

CC BY   
© 2009 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.