Structural Basis of glmS Ribozyme Activation by Glucosamine-6-Phosphate
Abstract
The glmS ribozyme is the only natural catalytic RNA known to require a small-molecule activator for catalysis. This catalytic RNA functions as a riboswitch, with activator-dependent RNA cleavage regulating glmS messenger RNA expression. We report crystal structures of the glmS ribozyme in precleavage states that are unliganded or bound to the competitive inhibitor glucose-6-phosphate and in the postcleavage state. All structures superimpose closely, revealing a remarkably rigid RNA that contains a preformed active and coenzyme-binding site. Unlike other riboswitches, the glmS ribozyme binds its activator in an open, solvent-accessible pocket. Our structures suggest that the amine group of the glmS ribozyme-bound coenzyme performs general acid-base and electrostatic catalysis.
- Publication:
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Science
- Pub Date:
- September 2006
- DOI:
- 10.1126/science.1129666
- Bibcode:
- 2006Sci...313.1752K
- Keywords:
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- BIOCHEM