Abstract
This work deals with the synthesis of 6-methyl-3-[(4′-methylphenyl)imino]methyl-4H-chromen-4-one (MMPIMC), its binding to β-cyclodextrin, and the influence of the cyclodextrin complexation on the compound’s binding to bovine serum albumin (BSA). The 1:2 stoichiometry for the complexation of MMPIMC with β-cyclodextrin is determined with the binding constant of 1.90 × 104 M−2. The structure of host–guest complex plays a role in protein binding of MMPIMC. One- and two-dimensional NMR spectra are used to determine the mode of binding of the guest to β-cyclodextrin cavity and the structure of the inclusion complex is proposed. The binding of MMPIMC with BSA in the absence and the presence of β-cyclodextrin is studied. The binding strengths of MMPIMC–BSA (1.73 × 105 M−1) and β-cyclodextrin-complexed MMPIMC–BSA (9.0 × 104 M−1) show difference in magnitude. The Förster Resonance Energy Transfer efficiency and the proximity of the donor and acceptor molecules, are modulated by β-cyclodextrin. Molecular modeling is used to optimize the sites and mode of binding of MMPIMC with bovine serum albumin.
Acknowledgments
This work is financially supported by the SERB–Department of Science and Technology (DST), Government of India (Project file: SR/FT/CS-062/2009). We express our sense of gratitude to the DST. SAIF, Indian Institute of Technology–Madras, Chennai, helped in NMR measurements. We thank the Dean-Research and the Chancellor of Karunya University.