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Solution NMR studies on the physiologically relevant ligand-free and maltotriose-bound states of maltodextrin-binding protein (MBP) are presented. Together with existing data on MBP in complex with β-cyclodextrin (non-physiological, inactive ligand), these new results provide valuable information on changes in local structure, dynamics and global fold that occur upon ligand binding to this two-domain protein. By measuring a large number of different one-bond residual dipolar couplings, the domain conformations, critical for biological function, were investigated for all three states of MBP. Structural models of the solution conformation of MBP in a number of different forms were generated from the experimental dipolar coupling data and X-ray crystal structures using a quasi-rigid-body domain orientation algorithm implemented in the structure calculation program CNS. Excellent agreement between relative domain …