Title
Silver (I) Induced Conformation Change of DNA: Gold Nanocluster as Spectroscopic Probe
Author
Dipankar Bain, Bipattaran Paramanik, Amitava Patra
Year
2016
Journal
The Journal of Physical Chemistry C
Abstract
DNA based materials are promising avenues for designing optical sensors, light harvesting device, energy conversion device and other potential applications. Therefore, the understanding of DNA conformation is important for designing such materials. Here, we investigate the conformation of DNA by photo excited energy transfer process where Au cluster is covalently attached with AlexaFluor 488 (A488) dye tagged DNA. Fluorescence resonance energy transfer (FRET) is a well known method to determine the donor-acceptor distance where A488 acts as donor and the gold nanoclusters (Au NCs) acts as acceptor. Spectroscopic studies reveal that Ag+ ions are incorporated into dsDNA to produce Ag+-C (cytosine) metal base pair bond as the used DNA contains 55.6 % G-C base pairs. Steady state and time resolved spectroscopic studies reveal that the distances between donor and acceptor are found to be 98 Å and 83 Å in absence and presence of Ag+ ion, respectively, indicating the rigid conformation of dsDNA becomes flexible in presence of Ag+ ion. The efficiency of energy transfer increases from 63% to 82% in presence Ag+ ion because the conformation of DNA changes with the formation of DNA-metal base pairs. Analysis suggests that Au cluster is a useful spectroscopic probe to understand the conformation of DNA and other. Furthermore, this energy transfer from dye to Au NCs using DNA scaffold may open up new opportunities in designing artificial light harvesting system.
Full Article
Instrument
J-815
Keywords
Circular dichroism, DNA structure, Ligand binding, Biochemistry