Functional equivalence of the uridine turn and the hairpin as building blocks of tertiary structure in the Neurospora VS ribozyme. |
| |
Authors: | V D Sood R A Collins |
| |
Affiliation: | Department of Molecular and Medical Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada. |
| |
Abstract: | Mutational, kinetic, and chemical modification experiments show that one of the three-way helical junctions in the Neurospora VS ribozyme contains a uridine turn that is important for organizing the functional three-dimensional structure of this junction. Disruption of the uridine turn disrupts the structure of the junction and decreases the self-cleavage activity of the ribozyme; however, substitution of the uridine turn with a variety of different hairpins, thereby transforming the three-way junction into a four-way junction, maintains catalytic activity. Chemical modification structure probing reveals that both the native junction and the hairpin-containing junction support the same tertiary interactions required elsewhere in the ribozyme for catalysis. These observations show that functionally equivalent three-dimensional RNA structures can be built from different secondary structure elements. |
| |
Keywords: | |
|
|