Study of the BPP7a peptide and its β-cyclodextrin complex: physicochemical characterization and complete sequence specific NMR assignments
摘要:
The BPP7a heptapeptide, p-Glu(1)Asp(2)Gly(3)Pro(4)Ile(5)Pro(6)Pro(7), forms an association complex with beta-cyclodextrin in a 1: 1 molar ratio. The peptide and its complex were characterized by circular dichroism (CD) and isothermal titration calorimetry (ITC), which showed a very weak interaction between the beta-cyclodextrin and the peptide. Assignments of all hydrogen resonances of the peptide alone and as a complex were made using H-1 nuclear magnetic resonance (NMR) experiments at 400 and 600 MHz. High resolution diffusion ordered spectroscopy (HR-DOSY) experiments were carried out to establish the self-aggregation state of BPP7a. It was also shown that the beta-cyclodextrin breaks the molecular clusters leading to complex formation. In addition, the anti-hypertensive activity of the BPP7a/beta-cyclodextrin complex was evaluated in spontaneous hypertensive rats (SHR), showing increased activity compared to that of pure BPP7a.