Metal-dependent global folding and activity of the 8-17 DNAzyme studied by fluorescence resonance energy transfer

INOR 145

Hee-kyung Kim, hkim11@uiuc.edu1, Juewen Liu, jliu2@uiuc.edu1, Jing Li1, Nandini Nagraj1, Mingxi Li2, Caroline Pavot1, and Yi Lu1. (1) Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Matthews Ave, Urbana, IL 61801, (2) Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL
The 8-17 DNAzyme is a DNA metalloenzyme catalyzing RNA transesterification in the presence of divalent metal ions, with activity following the order of Pb2+ >> Zn2+ >> Mg2+. Metal-induced global folding of the DNAzyme was studied by fluorescence resonance energy transfer (FRET) in order to gain insight on the role of different metals in its structure and function. FRET results indicated that, in the presence of Zn2+ and Mg2+, the DNAzyme folds into a compact structure. Correlations between metal-induced folding and activity were also studied. For Zn2+ and Mg2+, the metal ion with higher affinity for the DNAzyme in global folding also displays higher affinity in activity. Surprisingly, no Pb2+ -dependent global folding was observed. These results suggest that for Pb2+, global folding of the DNAzyme may not be a necessary step in its function, which may contribute to the DNAzyme having the highest activity in the presence of Pb2+.
 

Bioinorganic Chemistry: DNA and RNA
1:30 PM-5:30 PM, Sunday, August 19, 2007 BCEC -- 211, Oral

Division of Inorganic Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007