The structure of the metal ion complexed purine nucleotides and specifically the proximity of the aromatic portion of the purine nucleotide to the metal ion binding site suggest that the two are within bonding distance. This was investigated using fluorescence spectroscopy by binding the fluorescent lanthanide Tb(III) to each of the three adenosine nucleotides (AMP, ADP, and ATP). These nucleotides were excited at 260nm and emission intensity was determined at 540nm, 545nm and 550nm. The results indicated that adenosine monophosphate had the greatest increase in fluorescence intensity, followed by adenosine diphosphate and then adenosine triphosphate. It is believed that the increase in fluorescence intensity was directly related to the distance between the excited aromatic portion of the nucleotide and the bound Tb(III). In terms of energy transfer, these results suggest that Tb(III) bound to AMP exhibited the most efficient energy transfer with successively less for ADP and ATP.

Metal ion-nucleotide interactions

240th National Meeting (2010)

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