Capturing hammerhead ribozyme structures in action by modulating general base catalysis.
| Autor: | Young-In Chi, Monika Martick, Monica Lares, Rosalind Kim, William G Scott, Sung-Hou Kim |
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| Jazyk: | angličtina |
| Rok vydání: | 2008 |
| Předmět: | |
| Zdroj: | PLoS Biology, Vol 6, Iss 9, p e234 (2008) |
| Druh dokumentu: | article |
| ISSN: | 1544-9173 1545-7885 |
| DOI: | 10.1371/journal.pbio.0060234 |
| Popis: | We have obtained precatalytic (enzyme-substrate complex) and postcatalytic (enzyme-product complex) crystal structures of an active full-length hammerhead RNA that cleaves in the crystal. Using the natural satellite tobacco ringspot virus hammerhead RNA sequence, the self-cleavage reaction was modulated by substituting the general base of the ribozyme, G12, with A12, a purine variant with a much lower pKa that does not significantly perturb the ribozyme's atomic structure. The active, but slowly cleaving, ribozyme thus permitted isolation of enzyme-substrate and enzyme-product complexes without modifying the nucleophile or leaving group of the cleavage reaction, nor any other aspect of the substrate. The predissociation enzyme-product complex structure reveals RNA and metal ion interactions potentially relevant to transition-state stabilization that are absent in precatalytic structures. |
| Databáze: | Directory of Open Access Journals |
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