A glycine-dependent riboswitch that uses cooperative binding to control gene expression.

Maumita Mandal1, Mark Lee,2 Jeffrey E. Barrick,2 Zasha Weinberg,3 Gail Mitchell Emilsson,1 Walter L. Ruzzo,3,4 and Ronald R. Breaker1

Science. 2004 Oct 8;306(5694):275-9.

Abstract:  We identified a previously unknown riboswitch class in bacteria that is selectively triggered by glycine. A representative of these glycine-sensing RNAs from Bacillus subtilis operates as a rare genetic on switch for the gcvT operon, which codes for proteins that form the glycine cleavage system. Most glycine riboswitches integrate two ligand-binding domains that function cooperatively to more closely approximate a two-state genetic switch. This advanced form of riboswitch may have evolved to ensure that excess glycine is efficiently used to provide carbon flux through the citric acid cycle and maintain adequate amounts of the amino acid for protein synthesis. Thus, riboswitches perform key regulatory roles and exhibit complex performance characteristics that previously had been observed only with protein factors.

1Department of Molecular, Cellular, and Developmental Biology, 2Department of Molecular Biophysics and Biochemistry, Yale University, Post Office Box 208103, New Haven, CT 06520-8103, USA.
3Department of Computer Science and Engineering, 4Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA.

E-mail: ruzzo /at/ cs /dot/ washington /dot/ edu