Structural Basis of glmS Ribozyme Activation by Glucosamine-6-Phosphate

作者：Daniel J. Klein, A.R. Ferré-D′Amaré · 发表于：Science · 年份：2006 · DOI：10.1126/science.1129666 · 被引用次数：378 · 研究领域：RNA and protein synthesis mechanisms、Chemical Synthesis and Analysis、RNA modifications and cancer

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.