COLL 12 |
| Gonzalo Cosa1, Elizabeth J. Harbron1, Donald B. O'Connor1, Karin Musier-Forsyth2, and Paul F. Barbara1. (1) Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78751, (2) Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455 |
| Several nucleic acid rearrangement steps are involved in the reverse transcription of the HIV type-1 virus. The nucleocapsid protein (NC) of HIV type-1 plays a key role as a nucleic acid chaperone protein, facilitating the formation of the most stable structures. Single molecule fluorescence resonance energy transfer (SM-FRET) studies enable us to observe the conformational fluctuations of a transactivation response region (TAR) -DNA hairpin mimic labeled with a fluorescent donor and a fluorescent acceptor dye. SM-FRET results show conformational fluctuations of the TAR-DNA hairpin occurring in the 100 ms time scale following incubation with NC. These fluctuations encompass at least 35 bases in both arms of the hairpin and are non-cooperative in nature. No fluctuations are registered with the labeled TAR-DNA hairpin in the absence of NC or when a stable hairpin containing no bulges is analyzed. These data reports the first real-time observation of NC-mediated TAR-DNA hairpin conformational fluctuations. |
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Nanoscale Imaging of Biological Systems
Division of Colloid and Surface Chemistry |