科研之友
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摘要
A series of hybrid quantum mechanical/molecular mechanical (QM/MM) calculations was performed on models of a DNA duplex with artificial silver(I)-mediated imidazole base pairs. The optimized structures were compared to the original experimental NMR structure (Nat. Chem. 2 (2010) 229-234). The metal-metal distances are significantly shorter (similar to 0.5 angstrom) in the QM/MM model than in the original NMR structure. As a result, argentophilic interactions are feasible between the silver(l) ions of neighboring metal-mediated base pairs. Using the computationally determined metal metal distances, a re-refined NMR solution structure of the DNA duplex was obtained. In this new NMR structure, all experimental constraints remain fulfilled. The new NMR structure shows less deviation from the regular B-type conformation than the original one. This investigation shows that the application of QM/MM models to generate additional constraints to be used during NMR structural refinements represents an elegant approach to obtaining high-resolution NMR structures.
- 出版日期2013-10
