Removal of the A adenosine in a DNA-stabilized Ag nanocluster.

The role of the terminal adenosine (A) on the spectroscopic and structural properties of a previously described DNA-stabilized Ag nanocluster (DNA:AgNC) is presented. In the original DNA:AgNCs (5'-CACCTAGCGA-3'), the A nucleobase was involved in an Ag-mediated interaction with an A in a neighboring asymmetric unit, and did not interact with the AgNC. Therefore, we synthesized AgNCs embedded in the corresponding 9-base sequence in order to investigate the crystal structure of these new DNA-A:AgNCs and analyze the photophysical properties of the solution and crystalline state. The X-ray crystallography and spectroscopic measurements revealed that the 3'-end adenosine has little importance with respect to the photophysics and structure of the AgNCs. Additionally, the new crystallographic data was recorded with higher spatial resolution leading to a more detailed insight in the interactions between the nucleotides and Ag atoms.