What are riboswitches primarily recognized for?

Riboswitches are primarily recognized for their ability to change conformation when bound by a small molecule. This structural change allows riboswitches to regulate gene expression by affecting the stability of downstream messenger RNA (mRNA) or influencing the formation of regulatory structures. When a specific metabolite or ligand binds to the riboswitch, it induces a conformational alteration that can either promote or inhibit the synthesis of proteins, illustrating their role as regulatory elements in gene expression. This mechanism is a key feature of riboswitch functionality, enabling the cell to respond dynamically to changes in metabolic conditions by modulating its gene expression based on the concentration of certain metabolites.