Riboswitches: emerging themes in RNA structure and function.
Riboswitches are RNAs capable of binding cellular metabolites using a diverse array of secondary and tertiary structures to modulate gene expression. The recent determination of the three-dimensional structures of parts of six different riboswitches illuminates common features that allow riboswitches to be grouped into one of two types. Type I riboswitches, as exemplified by the purine riboswitch, are characterized by a single, localized binding pocket supported by a largely pre-established global fold. This arrangement limits ligand-induced conformational changes in the RNA to a small region. In contrast, Type II riboswitches, such as the thiamine pyrophosphate riboswitch, contain binding pockets split into at least two spatially distinct sites. As a result, binding induces both local changes to the binding pocket and global architecture. Similar organizational themes are found in other noncoding RNAs, making it possible to begin to build a hierarchical classification of RNA structure based on the spatial organization of their active sites and associated secondary structural elements.
Montange
Rebecca K
RK
Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA.
Batey
Robert T
RT
D015870:Gene Expression / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology*; D008956:Models, Chemical; D008957:Models, Genetic; D008958:Models, Molecular; D012313:RNA / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D013329:Structure-Activity Relationship
D016601:RNA-Binding Proteins; D012313:RNA