In molecular biology, a riboswitch is a regulatory segment of a messenger RNA molecule that binds a small molecule, resulting in a change in production of the proteins encoded by the mRNA. Thus, an mRNA that contains a riboswitch is directly involved in regulating its own activity, in response to the concentrations of its effector molecule. The discovery that modern organisms use RNA to bind small molecules, and discriminate against closely related analogs, expanded the known natural capabilities of RNA beyond its ability to code for proteins, catalyze reactions, or to bind other RNA or protein macromolecules. Most known riboswitches occur in bacteria, but functional riboswitches of one type (the TPP riboswitch) have been discovered in archaea, plants and certain fungi. Riboswitches are often conceptually divided into two parts: an aptamer and an expression platform. The aptamer directly binds the small molecule, and the expression platform undergoes structural changes in response to the changes in the aptamer. The expression platform is what regulates gene expression. Here you can see the crystal structure of the E. coli thiM riboswitch (PDB code: 7TZR)
#molecularart ... #immolecular ... #riboswitch ... #RNA ... #bacteria ... #escherichia ... #aptamer ... #xray
Structure of the bacterial riboswitch rendered with @proteinimaging and depicted with @corelphotopaint
#molecularart ... #immolecular ... #riboswitch ... #RNA ... #bacteria ... #escherichia ... #aptamer ... #xray
Structure of the bacterial riboswitch rendered with @proteinimaging and depicted with @corelphotopaint
