A Conformational Change in the Catalytic Core of the Hammerhead Ribozyme upon Cleavage of an RNA Substrate†

1. How do ribozymes work? 2412. The hammerhead RNA as a prototype ribozyme 2422.1 RNA enzymes 2422.2 Satellite self-cleaving RNAs 2422.3 Hammerhead RNAs and hammerhead ribozymes 2443. The chemical mechanism of hammerhead RNA self-cleavage 2463.1 Phosphodiester isomerization via an SN2(P) reaction 2473.2 The canonical role of divalent metal ions in the hammerhead ribozyme reaction 2513.3 The hammerhead ribozyme does not actually require metal ions for catalysis 2543.4 Hammerhead RNA enzyme kinetics 2574. Sequence requirements for hammerhead RNA self-cleavage 2604.1 The conserved core, mutagenesis and functional group modifications 2604.2 Ground-state vs. transition-state effects 2615. The three-dimensional structure of the hammerhead ribozyme 2625.1 Enzyme–inhibitor complexes 2625.2 Enzyme–substrate complex in the initial state 2645.3 Hammerhead ribozyme self-cleavage in the crystal 2645.4 The requirement for a conformational change 2655.5 Capture of conformational intermediates using crystallographic freeze-trapping 2665.6 The structure of a hammerhead ribozyme ‘early’ conformational intermediate 2675.7 The structure of a hammerhead ribozyme ‘later’ conformational intermediate 2685.8 Is the conformational change pH dependent? 2695.9 Isolating the structure of the cleavage product 2715.10 Evidence for and against additional large-scale conformation changes 2745.11 NMR spectroscopic studies of the hammerhead ribozyme 2786. Concluding remarks 2807. Acknowledgements 2818. References 2811. How do ribozymes work? 241The discovery that RNA can be an enzyme (Guerrier-Takada et al. 1983; Zaug & Cech, 1986) has created the fundamental question of how RNA enzymes work. Before this discovery, it was generally assumed that proteins were the only biopolymers that had sufficient complexity and chemical heterogeneity to catalyze biochemical reactions. Clearly, RNA can adopt sufficiently complex tertiary structures that make catalysis possible. How does the three- dimensional structure of an RNA endow it with catalytic activity? What structural and functional principles are unique to RNA enzymes (or ribozymes), and what principles are so fundamental that they are shared with protein enzymes?

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Sequence elements outside the hammerhead ribozyme catalytic core enable intracellular activity

Nature Structural & Molecular Biology ◽

10.1038/nsb959 ◽

2003 ◽

Vol 10 (9) ◽

pp. 708-712 ◽

Cited By ~ 268

Author(s):

Anastasia Khvorova ◽

Aurélie Lescoute ◽

Eric Westhof ◽

Sumedha D Jayasena

Keyword(s):

Hammerhead Ribozyme ◽

Catalytic Core ◽

Intracellular Activity ◽

Sequence Elements

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Sequence elements outside the catalytic core of natural hairpin ribozymes modulate the reactions differentially

Biological Chemistry ◽

10.1515/bc.2011.071 ◽

2011 ◽

Vol 392 (7) ◽

Cited By ~ 4

Author(s):

Preeti Bajaj ◽

Gerhard Steger ◽

Christian Hammann

Keyword(s):

Mutational Analysis ◽

Hammerhead Ribozyme ◽

The Other ◽

Hairpin Ribozyme ◽

Catalytic Core ◽

Arabis Mosaic Virus ◽

Sequence Elements ◽

Satellite Rnas ◽

Hairpin Ribozymes

AbstractHairpin ribozymes occur naturally only in the satellite RNAs of tobacco ringspot virus (TRsV), chicory yellow mottle virus (CYMoV) and arabis mosaic virus (ArMV). The catalytic centre of the predominantly studied sTRsV hairpin ribozyme, and of sArMV is organised around a four-way helical junction. We show here that sCYMoV features a five-way helical junction instead. Mutational analysis indicates that the fifth stem does not influence kinetic parameters of the sCYMoV hairpin ribozymein vitroreactions, and therefore seems an appendix to that junction in the other ribozymes. We report further that all three ribozymes feature a three-way helical junction outside the catalytic core in stem A, with Watson-Crick complementarity to loop nucleotides in stem B. Kinetic analyses of cleavage and ligation reactions of several variants of the sTRsV and sCYMoV hairpin ribozymesin vitroshow that the presence of this junction interferes with their reactions, particularly the ligation. We provide evidence that this is not due to a presumed interaction of the afore-mentioned elements in stems A and B. The evolutionary survival of thiscis-inhibiting element seems rather to be caused by the coincidence of its position with that of the hammerhead ribozyme in the other RNA polarity.

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