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Tertiary structure stability of the hairpin ribozyme in its natural and minimal forms : different energetic contributions from a ribose zipper motif

Klostermeier, D. and Millar, D. P.. (2001) Tertiary structure stability of the hairpin ribozyme in its natural and minimal forms : different energetic contributions from a ribose zipper motif. Biochemistry, Vol. 40, H. 37. pp. 11211-11218.

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Official URL: http://edoc.unibas.ch/dok/A5259719

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Abstract

The hairpin catalytic motif in tobacco ringspot virus satellite RNA consists of two helix-loop-helix elements on two adjacent arms of a four-way helical junction. The bases essential for catalytic activity are located in the loops that are brought into proximity by a conformational change as a prerequisite for catalysis. The two loops interact via a ribose zipper motif involving the 2'-hydroxyls of A10, G11, A24, and C25 [Rupert, P. B., and Ferre d'Amare, A. R. (2001) Nature 401, 780-786]. To quantify the energetic importance of the ribose zipper hydrogen bonds, we have incorporated deoxy modifications at these four positions and determined the resulting destabilization of the docked conformer by means of time-resolved fluorescence resonance energy transfer. In a minimal form of the ribozyme, in which the loops are placed on the arms of a two-way helical junction, all modifications lead to a significant loss in tertiary structure stability and altered Mg2+ binding. Surprisingly, no significant destabilization was seen with the natural four-way junction ribozyme, suggesting that hydrogen bonding interactions involving the 2'-hydroxyls do not contribute to the stability of the docked conformer. These results suggest that the energetic contributions of ribose zipper hydrogen bonds are highly context dependent and differ significantly for the minimal and natural forms of the ribozyme.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Former Organization Units Biozentrum > Biophysical Chemistry (Klostermeier)
UniBasel Contributors:Klostermeier, Dagmar
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
Publisher:American Chemical Society
ISSN:0006-2960
Note:Publication type according to Uni Basel Research Database: Journal article
Last Modified:22 Mar 2012 14:21
Deposited On:22 Mar 2012 13:23

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